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Part 1 Animal science.


Hackamore--A type of head restraint for horses similar to a halter but provided with a loop or noose that may be placed about the nose of the horse to give additional restraint in handling unbroken horses. Also called jaquima, headstall.

Hackles--(1) The long, narrow, neck plumage of male birds. (2) The erectile hairs on the backs of certain animals.

Hackney--A breed of light harness or carriage horses that originated on the east coast of England, averaging from fifteen to sixteen hands high and having considerable depth through the chest and body. It lifts its forefeet in an exaggerated manner. The preferred coat colors are chestnut and bay.

Hackney Pony--A breed of harness ponies which resulted from crossing a Hackney stallion and a pony mare of Welsh breeding. in general, it is similar to the Hackney except for size, being fourteen hands high or less.

Haemonchosis (Hemonchosis)--The infection of ruminants with the large stomach worm, species of the genus Haemonchus, or the disease caused by this parasite. Haemonchosis is usually accompanied by loss of blood and anemia caused by the activities of the worms, and it is one of the most serious helminthic diseases of ruminants.

Hair--The outgrowth of a cell in the epidermis of a plant or animal. In vast numbers it forms the coat of an animal and is frequently used as a fiber, such as wool. See Pubescent, Root Hair.

Hair Ball--Hair an animal has swallowed that has gathered in the stomach in the form of a ball; common in the stomach of cats and in the rumen of ruminants. Also called aegagropila, egagropilus, piliconcretion, trichobezoar. See Bezoar, Stomach Ball.

Hair Slips--An animal hide that has been improperly salted and cured, allowing some decomposition to take place as indicated by slipping patches of hair.

Hairlessness--(1) In genetics, a lethal factor characterized in the Holstein breed by calves being born without hairs except around natural openings and at the end of the tail. (2) An iodine-deficiency disease that causes pigs to be born hairless. See Iodine.

Half Cheek Snaffle Bit--A type of snaffle bit used with racing harness horses. See Snaffle Bit.

Half Sisters--Queen or worker bees produced by a single queen and sired by drones that are not related to each other.

Half-blood Wool--The designation of a grade of wool classified immediately below the fine grade.

Half-bred--Designating a horse that has a Thoroughbred as one parent and a draft horse as the other. A popular, medium-heavyweight horse with considerable action.

Half-brother (Half-sister)--Animals from the same mother but by different sires, or by the same sire from different mothers.

Half-sib--A half-brother or half-sister.

Halfbreed--(1) A cross between two botanical varieties of the same species. (2) A cross between two races.

Halter--A leather, rope, or chain device that is essentially a loop over an animal's nose and another loop behind the ears for leading or restraining.

Ham--A cut of pork that consists of the hindquarters of a swine from the hock to the hip, including the thigh and buttock; specifically, one that has been salt-cured and smoked. See Fresh Ham, Picnic Ham.

Ham Butt--A retail cut of pork that consists of the thigh end of ham.

Ham String--The large tendon above and behind the hock in the hind leg of quadrupeds.

Hamburg(er)--Retail meat which consists of ground lean and fat beef (except that no heart, liver, kidney, etc., is used).

Hame--The wood or metal parts of the harness of a draft animal that fit about the collar to which the traces are attached for pulling.

Hammerhead--A coarse-headed animal.

Hampshire--(1) A medium-wool, black-faced breed of sheep that originated in England. It is a popular mutton breed whose ewes weigh up to 100 pounds. (2) An American breed of black, white-belted swine.

Hamstrung--Designating an injury to the tendon behind the cannon in the hind leg of an animal.

Hand--(1) A laborer who is either permanently employed or migratory, as harvest hand, hired hand. (2) A unit of measurement equal to 4 inches (10 centimeters) that is used to measure the height of horses from the ground to a point at the shoulder. (3) A bunch of tobacco leaves of the same grade that are tired together for easier handling. (4) The near horse in a team used for plowing. (5) A half-whorl-like cluster of bananas attached to the rachis of the spike or bunch. (6) Designating any tool, implement, etc., that is manually operated. (7) Designating any manual labor, as hand chopping.

Hand Breeding (Hand Mating)--A system of animal breeding in which the breeder controls the number of times coitus is performed.

Hand Feeding--A type of feeding routine whereby an animal is fed measured amounts of food, water, salt, etc., at fixed intervals.

Hand Gallop--A restrained or slow gallop of horses. See Canter.

Hand Milker--A person who milks a cow manually.

Hand Strip--(1) To take the last bit of milk from a cow's udder, usually following machine milking. (2) To harvest a seed crop by hand.

Handiness--A characteristic of a horse with good manners who has good coordination, and is not clumsy or awkward in movement or action.

Handpick--(1) To harvest by hand, as contrasted to harvesting by machine. (2) To pluck the feathers of a fowl manually.

Hang--To age meat or game by hanging in a cool unrefrigerated place.

Haploid--An organism or cell with one set of chromosomes; for example, drone bee. See Diploid.

Haploid Number--In genetics, this is half (haploid) the number of chromosomes that are usually present in the nucleus; occurs during reduction division.

Hard Breeder--Designating a female animal that is difficult to breed or has difficulty conceiving.

Hard Feather--A term used in describing a plumage characteristic of game fowl. Hardness is dependent on the narrowness and shortness of the feather, toughness and substance of shaft, substance of the barbs, and the firm closely knitted character of the barbs forming the web and scanty fluff.

Hard Feeder--An animal that stays in a thin condition even though well fed. Sometimes called hard keeper.

Hard Keeper--An animal that is unthrifty and grows or fattens slowly regardless of the quantity and quality of feed. Also called hard feeder.

Hard Milker--A cow that milks slowly due to hardened or constricted sphincter muscles in the end of the teat, or a fleshy udder with limited space for the fast accumulation of milk.

Hard-mouthed--A term used when the membrane of the bars of a horse's mouth where the bit rests have become toughened and the nerves deadened because of the continued pressure of the bit.

Hardiness--The state of being hardy. See Hardy.

Hardware Disease--A condition found in ruminants in which metal objects, such as wire, nails, and screws, are swallowed with feed, and because of their weight, move from the paunch to the second stomach. Lodging there, the metal objects pierce the stomach wall, often causing severe damage, including abscesses, peritonitis, or death. Rod-shaped magnets called rumen magnets are given with a balling gun to an animal to minimize damage to stomach membranes by attracting and holding the metal objects in the paunch (rumen).

Harsh--(1) Designating a fleece that lacks character, as rough hair. (2) Designating vegetation that is rough, hard, or that has some physical characteristic objectionable to livestock.

Harvest--(1) To cut, reap, pick, or gather any crop or product of value, as grain, fruit, or vegetables. (2) The crop or product so harvested.

Hat Racks--Thin cattle; canners.

Hatch--(1) (a) To bring forth young from the egg by natural or artificial incubation. (b) The young produced from one incubation. (2) The access entryway to cellars, attics, haymows, ships, etc.

Hatch Out--To emerge from an egg, as a fully developed chick comes forth from the shell.

Hatchability--(1) In poultry farming, that quality of fertilized eggs when incubated that makes possible normal embryonic development and the emergence of normal young. (2) In incubation practice, the percentage of fertile eggs that hatch.

Hatchery--A place, building, company, etc., where eggs are incubated, usually a commercial establishment where newly hatched young (chicks, poults, ducklings, etc.) are sold.

Hatching Egg--A fertile egg of good form and quality produced by a breeding flock that may be used for hatching.

Haunch--(1) A pivot on the hind feet. It is commonly observed in stock horses used on ranches for culling or cutting. (2) A hindquarter of an animal.

Hay--Any leafy plant material, usually clover, fine-stemmed grasses and sedges, alfalfa, and other legumes, that has been cut and dried principally for livestock feeding. See Fodder, Marsh Hay.

Hay and Dairy Region--A region of the northeastern United States where grasses and legumes are naturally abundant or easily grown, and where the feed supply and barn and market sizes are generally more suitable for dairy cattle and milk production than for other types of farming, and where markets for dairy products are well established.

Hay Bale--A quantity of loose hay compressed usually into a rectangular bale about 3 feet by 18 inches by 14 inches, containing from 40 to 125 pounds depending on the kind of hay, degree of compaction, and moisture content. The compressed hay is held in the bale by baling wire, light metal strips, or heavy twine. More common are the large cylindrical bales weighing up to a ton or more.

Hay Belly--A term applied to animals having a distended barrel due to the excessive feeding of bulky rations, such as hay, straw, or grass.

Hay Fever--Allergic symptoms involving the upper respiratory tract caused by dust and/or pollen grains.

Hay Meadow--A field in which hay is grown.

Haylage--Forage that could have been cut for hay but is stored with a higher moisture content than hay, and with less moisture than silage.

Hays Converter--A breed of beef cattle developed in Canada from

Hereford and Brown Swiss.

Hazer--In rodeos, the assistant to the bulldogger who attempts to keep the animal running in a straight line and endeavors to protect the bulldogger from being gored.

Head--(1) Any tightly formed flower cluster, as in members of the family Compositae, or any tightly formed fruit cluster, as the head of wheat or sunflower. (2) A compact, orderly mass of leaves, as a head of lettuce. (3) On a tree, the point or region at which the trunk divides into limbs. (4) The height of water above any point of reference (elevation head). The energy of a given nature possessed by each unit weight of a liquid expressed as the vertical height through which a unit weight would have to fall to release the average energy possessed, used in various compounds, as pressure head, velocity head, lost head, etc. (5) Cows, asses, horses, collectively, as ten head of horses. (6) The part of the body that includes the face, ears, brain, etc. (7) The source of a stream; specifically the highest point upstream at which there is a continuous flow of water, although a channel with an intermittent flow may extend farther. (8) The upstream terminus of a gully. (9) To prune a tree severely. (10) To get in front of a band of sheep, herd of cattle, etc., so as to stop their forward movement (head them off). (11) To place a top on a barrel. (12) That part of an engine that forms the top of the combustion chamber. In many types of modern engines, the exhaust and intake valves are in the head.

Head Shy--Designating a horse on which it is difficult to put a bridle, to lead, or to work around its head.

Headstall--The part of a bridle that encircles a horse's head.

Headstrong--Designating an animal that tends to be stubborn.

Health--The state wherein all body parts of plants, animals, and people are functioning normally.

Heart--(1) The organ of the body that by its rhythmical contractions circulates the blood. It is an edible by-product of slaughter animals and fowls. (2) The center portion of fruits and vegetables.

Heart-girth--A measurement taken around the body just back of the shoulders of an animal, used to indicate fullness of the chest and lung capacity and/or body weight.

Heat--(1) To ferment as a result of wet-stored grains such as wheat, corn, or barley, and forages; sometimes resulting in spontaneous combustion. (2) An animal in heat is ready to breed. See Estrus.

Heat Detection--The process used in determining females that are in estrus. See Gomer Bull.

Heat Mount Detector--A plastic device that is glued to the tailhead of a cow to determine when she comes into heat. Prolonged pressure from a mounting animal's brisket turns the detector a different color.

Heat Period--Estrus; the period during which a female is sexually receptive.

Heat Prostration--Heat stroke; a condition of a person or an animal resulting from excessively hot weather; characterized by lethargy, inability to work, staggering gait, convulsions, and high temperature. Death often occurs.

Heat Spot--A defect of a fertile egg that results from alternating high and low temperatures; characterized by the beginning of the development of the embryo without blood showing.

Heat Synchronization--Causing a group of cows or heifers to exhibit heat together at one time by artificial manipulation of the estrous cycle.

Heat-resistant--(1) Designating a variety or a species that grows under comparatively high temperature conditions; e.g., cotton and rattlesnakes. (2) Any material that is resistant to high temperatures.

Heat-tolerant--Designating the ability of an animal or plant to endure extreme heat conditions.

Heath--(1) Any plant of the genus Erica, family Ericaceae. Species are evergreen shrubs and small trees grown in greenhouses and out-of-doors. Also called erica. (2) A natural land feature, an extensive tract of uncultivated land, treeless or nearly so, which is covered by a dense growth of shrubby, ericaceous plants. It may be nearly the same as a high moore. Heaths are generally sandy and the soils strongly acid.

Heaves--An incurable respiratory disease of horses characterized by difficult breathing in which the air cells of the lungs are dilated or ruptured. It is thought to be caused by hard exercise, by consumption of dusty feed, or by heredity. It is found most frequently in old horses and is characterized by forced, double exhaling. Also called broken wind, chronic alveolar emphysema.

Heavy--(1) Designating any material or product that exhibits a comparatively high weight per unit volume. (2) Designating a clay or clayey soil that is difficult to plow. (3) In marketing, designating an abundant supply of a product for sale on one day at one market. (4) The late stages of pregnancy of a cow.

Heavy Breed--A bird (usually referring to a chicken) that has a high meat-to-bone ratio and is therefore suitable for the table. See Broiler.

Heavy Burning--Range firing during the dry, hot season to ensure a fire that will destroy the existing cover, facilitate travel and livestock handling, increase forage for livestock and game, and enhance hunting.

Heavy Grazing--The practice of keeping a large number of animal units on a pasture or range so that the grass or herbage may be closely grazed. Recommended prior to reseeding the pasture or range.

Heavy Wool--Wool that has considerable grease or dirt and will have a high shrinkage in scouring.

Heavyweight Hunter--A classification of a riding horse used for hunting that can carry a rider weighing 190 pounds (86 kilograms) or more.

Heel--(1) The basal end of a plant stem cutting along with a piece of the older stem. (2) See Hock. (3) The end of the branches of a horseshoe. (4) The rear end of the foot.

Heel Fly--The adult form of the cattle grub or ox warble. See Cattle Grub.

Heel of the Round--A retail cut of beef: the heavy fleshing at the rear of the stifle joint that is cut as a roast.

Heifer--The young female of the cattle species; usually applies to the female that has not yet had a calf.

Heiferette--Used to describe a heifer that has calved once, perhaps prematurely, then was "dried up" and fed for slaughter.

Held--(1) The lower end of an ax or other tool handle encased by the metal portion of the tool. (2) Designating the controlling of an animal in a small space or by other controlling devices.

Heliophobous--An organism that grows best in the shade.

Helminths--Worm parasites, such as the flatworms (flukes and tapeworms) and roundworms (hookworms and lungworms).

Helolac--A lake covered by a mat of aquatic plants such as water lilies, water hyacinth, or alligator weed.

Hematoma--Tumor containing effused blood.

Hematopoiesis--Formation or production of blood.

Hematuria--The presence of blood in urine.

Hemi--(Greek) Prefix meaning half.

Hemiparasite--A partial parasite.

Hemizygous--The condition in which only one allele of a pair of genes is present in the cells of an individual plant or animal, the other one being absent.

Hemlock Poisoning--Poisoning of animals resulting from browsing poison hemlock, Conium maculatum, family Apiaceae; characterized by cessation of digestion, gas, salivation, dilation of the pupils, rapid pulse and breathing, paralysis, unsteady gait, difficult breathing, and death.

Hemoglobin--The red pigment in the red blood cells of people and animals that carries oxygen from the lungs to other parts of the body.

Hemoglobin is a complex chemical compound, made up of iron, carbon, hydrogen, and oxygen, and is essential to life in red-blooded animals.

Hemoglobinuria--The presence of hemoglobin in the urine that is a symptom of some disease: e.g., cattle tick fever and azoturia. Bacillary disease of cattle and sheep is known to occur in western and parts of southern United States. The causative organism is Clostridium hemolyticum. See Cattle Tick Fever.

Hemolysis--The destruction of red blood cells and the resulting escape of hemoglobin.

Hemophilia--A hereditary condition of people and animals in which the blood does not coagulate readily and the slightest wound or bruise can cause considerable loss of blood. An animal so affected is often called a bleeder.

Hemorrhage--(1) Any escape or discharge of blood from the blood vessels. (2) To bleed.

Hemorrhagic Enteritis--An inflammatory condition of the intestines in which the small vessels (capillaries) in the lining become engorged and eventually rupture, allowing blood to seep into the intestine. The evacuations are watery and bloody or very dark-colored due to decomposition of the blood present in them.

Hemorrhagic Ova--Immature eggs (ova) that contain blood in the diseased ovary of poultry suffering from pullorum disease or avian typhoid.

Hemorrhagic Septicema--An infectious disease of livestock characterized by numerous, small hemorrhages in the tissues and the presence of bacteria of the pasteurella group and their associated poisons in the blood. Sometimes called shipping fever, stockyard fever, blood poisoning.

Hemostatics--Substances that check internal hemorrhage.

Hen--A female fowl; specifically, the female domestic fowl valued for its egg production.

Hen Battery--A number of individual hen-cage units arranged in a group, usually single or multiple decks, which have provision for watering, feeding, collecting eggs, and disposing of droppings.

Hennery--(1) A poultry farm, particularly one that specializes in the production of market eggs. (2) A building or enclosure where laying hens are kept.

Hepatitis--Inflammation of the liver.

Herbivorous--Designating an animal (herbivore) that feeds, in the native state, on grass and other plants, as cattle, horses, sheep, goats, deer, elk, etc. See Carnivore.

Herd--(1) A group of animals (especially cattle, horses, swine), collectively considered as a unit in farming or grazing practice. See Flock. (2) To tend animals in herds. See Cowboy, Herder, Shepherd.

Herd Book--The recognized, official record of the ancestry of a purebred animal kept by the particular breed association. The first herd book for keeping thoroughbred pedigrees was started in England in 1791. This was followed by Coates Herd Book for Shorthorns started in England in 1822.

Herd Bull Battery--All of the bulls in service in particular herds.

Herd Improvement Registry--A type of registry maintained by certain purebred cattle breeder associations to record the production and yearly records of all producing cows of that breed in a given breeder's herd.

Herd Sire--The male of the species kept for the sole purpose of reproduction. (The term is most commonly applied to cattle and horses but is also used with sheep and swine.) See Bull, Ram, Stallion.

Herd Test--A type of semi-official testing for milk production in which the whole herd of cows of milking age are included. This test was first started by the Ayrshire Breeders Association in 1925 and places the emphasis on the entire herd as a unit rather than on an individual cow.

Herding--The control of animals on the range by guiding their direction and movements to procure grazing and water where and when desired.

Heredity--(1) A study or description of genes passed from one generation to the next through sperm and ova. The heredity of an individual would be the genes received from the sire and dam via the sperm and ovum. (2) Genetic transmission of traits from parents to offspring. (3) The genetic constitution of an individual.

Hereford--A leading breed of beef cattle that originated in England. They are light to dark red with a characteristic white face and underline. Certain strains of the breed are polled (hornless). Also called white face. See Polled Hereford.

Hereford Swine--An American-developed breed of swine that has color markings similar to Hereford cattle.

Heritability--The proportion of the differences among animals, measured or observed, that is transmitted to the offspring. Heritability varies from zero to one. The higher the heritability of a trait, the more accurately does the individual performance predict breeding value and the more rapid should be the response due to selection for that trait.

Heritability Percent Estimates--The percent of a trait that is inherited from an animal's parents and is not controlled by environment.

Hermaphrodite--A bisexual individual that possesses both male and female sex organs. In some species such individuals are capable of reproducing, while in others they are sterile.

Hernia--The protrusion of internal organs through an opening in the body wall of humans or animals, as with a scrotal or umbilical hernia.

Heterogametic--Producing unlike gametes, particularly with regard to the sex chromosome. In species in which the male is of the "X-Y" type, the male is heterogametic, the female homogametic.

Heterogen--A variable group of plants or animals that arise as hybrids, sports, mutations, etc., certain types of which may or may not breed true.

Heterogeneous--Designating elements having unlike qualities.

Heterologous Serum--Serum derived from another species or disease.

Heterosis--The amount of superiority observed or measured in crossbred animals compared with the average of their purebred parents; hybrid vigor.

Heterotrophic--Referring to organisms that for their metabolism are dependent upon organic matter supplied from sources outside of their own bodies. See Autotrophic.

Heteroxenous Parasite--A parasite requiring several or different hosts for its complete development.

Heterozygous--An animal that carries genes for two different characters (impure).

Hexose--Any of various simple sugars that have six carbon atoms per molecule.

Hidden Hunger--Deficiency disease of plants or animals.

Hide--The tanned or untanned skins of animals, especially those of cattle, horses, sheep, and goats.

Hidebound--Designating an animal whose skin is very tightly fastened to its body, often resulting from poor feeding and emaciation.

Hidrosis--Excessive sweating.

High Blower--(1) A horse that has broken wind. (2) A horse that snorts at each exhalation while galloping.

High Lysine Corn--Corn that has a higher than normal content of lysine and tryptophan. This type corn has a better balance of amino acids for monogastric animals.

High School Horse--A horse trained for performing certain relatively highly complicated routines.

High-roller--Designating a horse whose bucking action is higher than usual.

Hilus--The stalk of the ovary that serves as the attachment to the broad ligament.

Hind Cinch--The rear cinch strap that encircles a horse to keep the saddle from tipping up when roping. In normal use, saddles have only one cinch that is fastened just behind the forelegs.

Hindgut--The posterior part of the alimentary canal between the midgut and anus.

Hinny--The offspring of a horse father and a donkey mother.

Hip--(1) The fruit of rose; rose hips. (2) The external angle (ridge) formed by the meeting of two sloping sides of a roof. (3) That region of one of the rear quarters of four-legged animals where the hind leg joins the pelvic region.

Hip Height--A measurement of cattle taken from the ground to the top of the hip. At a given age of the animal, hip height determines the frame score of a bull, steer, or heifer. See Frame Size.

Hippology--The study of the horse.

Hirsute--Covered with coarse hairs.

Hirudin--A substance extracted from the salivary glands of the leech that has the property of preventing coagulation of the blood.

Histamine--An alkaline type of chemical compound composed of carbon, hydrogen, and nitrogen which is probably formed in the animal body, mainly in the intestinal tract, by the action of bacteria on the amino acid, histidine. If it is absorbed into the bloodstream and circulated through the body, it may produce a fall in blood pressure, spastic contraction of the smooth muscles, and other symptoms, some of which may be relieved by antihistamine drugs.

Histology--The science of the microscopic structure of plant and animal cells.

Histopathologic--Designating abnormal changes in body structures, as observed by microscopic examination of sections of abnormal or diseased cells.

Histoplasmosis--A disease of the lymph nodes in the region of the neck caused by a fungus.

Hitch--(1) A catch; anything that holds, as a hook; a knot or noose in a rope, which can be readily undone, intended for a temporary fastening. (2) (a) The connecting of an implement, vehicle, etc., to a source of power, as a tractor, team, etc. (b) The device which is used to make such a connection. (3) A horse or horses used to pull an implement or vehicle. (4) The stride of a horse when one of the hind legs is shorter than the other. (5) To fasten an animal to a post, rail, etc.

Hitch Your Horse to the Ground--To let the reins of a horse drop to the ground for hitching purposes. Horses are trained to stay at a place when the reins are dropped on the ground.

Hive--A home for honeybees that is provided by people; it usually consists of a base, removable supers, and a top.

Hive Body--A single wooden rim or shell that holds a set of frames. When used for the brood nest, it is called a brood chamber; when used above the brood nest for honey storage, it is called a super. It may be of various widths and heights and adapted for comb honey sections.

Hive Cover--The roof or lid of a beehive.

Hive of Bees--A colony of honeybees living in a hive.

Hive Tool--A metal bar used to loosen frames and to separate the parts of a hive.

Hives--In horses, small swellings under or within the skin similar to human hives. They appear suddenly over large portions of the body and can be caused by a change in feed.

Hobble--(1) A thong that couples an animal's forelegs together to restrict its movements. (2) To tie an animal's forelegs so as to prevent straying.

Hock--(1) The region of the tarsal joint in the hind leg of a horse or other quadruped, corresponding to the angle in people. (2) The lower joint section of a ham.

Hock Hobbles--Hobbles that are used to fasten the hocks of the hind legs of a mare to prevent kicking preparatory to coitus.

Hoffman Frame--A self-spacing wooden frame used in Langstroth beehives.

Hog--See Swine.

Hog Bristles--The coarse, stiff hairs on swine used in the manufacture of brushes; now synthetic bristles have largely replaced hog bristles.

Hog Cholera--An acute, contagious, viral disease of swine characterized by sudden onset, fever, high morbidity, and mortality.

Hog Down (Hogging Off)--To pasture hogs on a crop grown for stock feed, thus eliminating the harvesting process. Also called hog off.

Hog Follicle Mite--Demodex phylloides, family Demodicidae; the demodex mange mite, a minute, skin parasite of swine that lives in hair follicles and sebaceous glands on the face, base of the tail, and the inner sides of the legs; it produces an inflammation of the skin that appears as small, hard pimples in size up to a marble. Upon breaking, the pimples discharge a yellowish-cheesy pus. Rare in hogs in the United States.

Hog Holder--A device consisting of a metal tube through which a cable is run. A loop on the end of the cable is placed on the snout of a hog to hold the hog for receiving vaccination, etc .

Hog Louse--Haematopinus suis, family Haematopinidae; the louse of the European wild boar, also found on domesticated swine in central Europe. H. adventicius chinensis is the common sucking louse of domesticated swine in North America.

Hog Ring--A ring that is fastened in the end of a hog's nose to prevent the hog from rooting in the ground.

Hog-Corn Ratio--See Corn-Hog Ratio.

Hog-dressed--Designating a dressed lamb or calf carcass with the head and pelt left on but with the feet viscera removed.

Hogg--A young yearling sheep before shearing.

Hohenheim System of Grazing--An intensive system of grassland management involving the division of the grazing area into a number of paddocks, grazed in rotation to allow a short period for growth between grazings. Nitrogenous fertilizers are usually applied after each grazing.

Hold--(1) To restrain animals to a particular place. (2) To remain on the tree until mature, as a fruit. (3) To retain, as certain soils hold moisture. (4) To maintain condition, as a steer that holds flesh. (5) To store or retain in storage, as to hold eggs. (6) Not to market at harvest time or when an animal is fat, but to wait to sell for a better price.

Hold Up Milk--In a cow, to cause a cessation in milk secretion as a result of undue excitement at milking time. See Let Down Milk.

Holding--An indefinite amount of land that is usually considered large in proportion to the average size of farms or ranches in its vicinity.

Holding Brand--A symbol or number burned into an animal's hide that is a requirement for registration with some cattle breed registry associations. The brand must be recorded in the association office.

Holding Ground--An area where livestock are often held during roundups; also called bunch ground.

Holding Pen--A large pen in which sheep or other animals are held prior to being handled.

Hollow Horn--An imaginary disease arising from the erroneous belief that loss of appetite and listlessness in a cow was due to hollow horns. The remedy was supposed to be (a) boring a hole in each horn just above the horn line, (b) filling the cavity with salt, sugar, and pepper, and (c) plugging the hole with a wooden peg. The belief was that if the cow had hollow horn this remedy would cure her, and if she did not have hollow horn, the remedy would prevent her getting it. See Hollow Tail.

Hollow Tail--An imaginary disease of a cow similar to hollow horn but which affected the tail. The remedy was supposed to be the same as for hollow horn, except that the hole or a slit was made in the tail. Also called wolf in the tail.

Holstein-Friesian--A widely used dairy breed of cattle. The name is American in origin but applies to cattle originally imported largely from the province of Friesland in Holland. They are black and white and the mature cows weigh from 1,100 to 1,800 pounds. They are noted for their high production of milk with a low butterfat content.

Homeostasis--Maintenance of a constant internal environment by a combination of body mechanisms.

Hominy Feed--A livestock feed that is a mixture of corn bran, corn germ, and part of the starchy portion of either white or yellow corn kernels or a mixture thereof as produced in the manufacture of pearl hominy, hominy grits, or table meal. It shall contain not less than 5 percent of crude fat. If prefixed with the words white or yellow, the product must correspond thereto. Also called hominy chop, hominy meal.

Homo--(Latin) (1) Man. (2) Prefix meaning alike or same. Homogametic--Refers to the particular sex of the species that possesses two of the same kind of sex chromosome such that only one kind of gamete can be produced with respect to the kinds of sex chromosomes it contains; in mammals, the female is the homogametic sex (XX).

Homogeneous--Being of uniform character or nature throughout.

Homogenized Milk--Milk that has been treated in such a way as to break up the particles or globules of fat to a size small enough that they will remain suspended and not rise to the top after standing. This is accomplished by passing the milk through small orifices under high pressure of 1,500 to 4,000 psi (10,341,000 to 27,576,000 pa) to disperse the fat globules so they will not rise as cream. Other substances such as margarine can also be homogenized.

Homolog--One of a pair of structures having similar structure, shape, and function, as with two homologous chromosomes.

Homologous--Organs or parts that exhibit similarity in structure, in position with reference to other parts, and in mode of development, but not necessarily similarity of function, are said to be homologous.

Homologous Chromosomes--Pairs of chromosomes that are the same length, that have their centrioles in the same position, and that pair up during synapsis in meiosis.

Homologous Serum--Serum that is derived from the same species or like disease.

Homothermic--Refers to animals that are able to maintain a fairly constant body temperature; warm-blooded.

Homothermous--Having the same temperature throughout.

Homozygote--An animal whose genotype, for a particular trait or pair of genes, consists of like genes.

Homozygous--Possessing identical genes with respect to any given pair or series of alleles.

Homozygous Recessive--A recessive character that produces two kinds of gametes; one carries the dominant gene, while the other carries the recessive gene.

Honda--A rope, rawhide, or metal loop at one end of a lariat through which the other end of the lariat is pulled to make a noose or large loop.

Honey--(1) An aromatic, viscid, sweet food material derived from the nectar of plants through collection by honeybees; modified by the bees into a denser liquid and finally stored in honeycombs. Of acid reaction, liquid in its original state, it becomes crystalline on standing. Honey consists chiefly of two simple sugars, dextrose and levulose, with occasionally more complex carbohydrates, with levulose usually predominant, and always contains minerals, plant coloring materials, several enzymes, and pollen grains. (2) Legally, the nectar and saccharine exudation of plants, gathered, modified, and stored in the comb by honeybees, which is levorotatory, and contains not more than 25 percent of water, not more than 0.25 percent ash, and not more than 8 percent sucrose.

Honey Bound--A condition under which the queen in a beehive is restricted in her egg-laying by the fact that all or most of the cells in the brood chamber are filled with honey.

Honey Butter--A mixture of creamery butter and 20 to 30 percent table quality, liquid honey used as a spread.

Honey House--Building in which honey is extracted and handled.

Honey Plant--Any plant from which honeybees gather nectar and pollen, especially one which either is in abundance or one which gives a distinctive flavor to honey.

Honey Stomach (Honey Sac)--An enlargement of the posterior end of the esophagus in the bee abdomen. It is the sac in which the bee carries nectar form flower to hive.

Honeybee--Apis mellifera, family Apidae; a very important economic insect that produces honey and acts as a pollinator of the flowers of many plants, both wild and cultivated.

Honeycomb--(1) The waxy structure in which honey is stored by bees. (2) A natural arrangement of the soil mass in more or less regular five- or six-sided sections separated by narrow or hairline cracks which is usually found as a surface structure. (3) See Reticulum.

Honeyflow--The incoming of nectar to the beehive, used especially in reference to the periodic changes in quantity related to the blooming periods of dominant flowering plants of the area, such as the clovers.

Hoof--The hard, horny, outer covering of the feet of horses, cattle, sheep, goats, and swine.

Hoof Pick--A tool used to clean the hoof of a horse or other animal.

Hoof-and-Mouth Disease--See Foot-and-Mouth Disease.

Hoofbound--A condition of horses, mules, etc., in which the hoof is dry and contracted, causing pain and occasional lameness.

Hook Bones--The prominent bones on the back of a cow formed by the anterior ends of the ilii (plural of ilium); points of the hip.

Hooks--See Hook Bones.

Hookworm--Any of certain internal, parasitic worms of animals and people that belong to the family Ancylostomatidae. The larvae, which are voracious bloodsuckers of the small intestine, are capable of penetrating the skin to gain entrance to the body, but may also gain entry by ingestion.

Hoose--A verminous bronchitis of cattle, sheep, and goats due to a lungworm infestation (a) of cattle chiefly by Dictyocaulus viviparus, (b) of sheep and goats chiefly by D. filaria, Protostrongylus rufescens, and Muellerius capillaris. Symptoms are a husky, spasmodic cough, emaciation, anemia, debility, thick nasal discharge, a breathing through the mouth. Also called husk. See Fowl Gapeworm.

Hopper-feeding--Making available to a rabbit, hog, or other animal a sufficient quantity of feed for several days so the animal may eat as often as it wishes and not be limited to a certain amount.

Horizontal Silo--A silo built with its long dimension parallel to the ground surface rather than perpendicular as in the case of an upright silo. It may be built just below the ground level with openings at both ends to facilitate filling and feeding.

Hormone--A chemical substance formed in some organ of the body, secreted directly into the blood, and carried to another organ or tissue, where it produces a specific effect.

Horn--(1) A natural, bonelike growth or projection on each side of the head of most breeds of cattle, sheep, and goats that is a natural weapon of defense. (2) The pointed end of a blacksmith's anvil used for shaping hot metal. (3) The front, upraised projection of a riding saddle, the snubbing horn. (4) The outer hard covering of the hoofs of horses, cattle, sheep, and swine. (5) A broad term commonly used in describing various shadings of color in the beak of some breeds of fowl.

Horn Fly--Siphona irritans, family Muscidae; a bloodsucking fly that infests cattle and goats. It probably causes greater loss in livestock production in the United States than any other bloodsucking fly.

Horn Weight--Ball-shaped weight, usually of lead, which is attached to the tips of the horns of show cattle to assist in the training and shaping of the horn growth.

Horned--Designating an animal that has horns. See Hornless, Polled.

Hornless--Designating a well-defined, polled condition of certain breeds of cattle, such as the Angus and Red Polled. See Polled.

Horny Frog--The semisoft, elastic, V-shaped structure in the sole of a horse's foot. Also called foot pad.

Horse--(1) Equus caballus; a quadruped of very ancient domestication used as a beast of burden, a draft animal, and a pleasure animal for riding, and in some areas as a meat animal. Breeds and types vary greatly in size and color from the Shetland pony to the Belgian. It has been important as one of the parents of the mule, and as a source of meat and hides. See Mule. (2) A stallion. (3) Designating an implement that is drawn by a horse.

Horse Bot Fly--Gasterophilus intestinalis, family Gasterophilidae; a fly that lays its eggs on the hairs of horses, usually on the front legs but sometimes on the shoulders, belly, or hind legs. When the horse licks himself the larvae cling to his lips or tongue. The larvae then burrow into the mucous membrane of the tongue working their way toward the base of the tongue. They pass to the stomach and remain there from nine to ten months, after which they release their hold on the walls of the stomach and pass to the ground in the excrement. They cause mechanical injury to the tongue, lips, lining of the stomach, and intestines, and they interfere with glandular action. They cause inflamed ulcerated conditions and absorb food that starves the host and may cause complete obstruction from the stomach to the intestines. Badly infested animals are run down, having digestive upsets, and rough coats. Also called common horse bot fly.

Horse Malaria--Equine infectious anemia.

Horse Manure--Dried horse excrement used as a medium for growing mushrooms, for making heat in hot beds, and as a soil amendment.

Horse Meat--In France, Belgium, and other parts of the world, horsemeat is considered a delicacy for human consumption. In the United States, many horses that have outlived their usefulness or that are less valuable for other purposes are processed in modern, sanitary slaughtering plants for pet food.

Horse Sleeping Sickness--See Encephalomyelitis.

Horse Sucking Louse--Haematopinus asini, family Haematopinidae; a bloodsucking, insect pest of horses, mules, and asses. Infestation is characterized by scurfy skin, loss of vitality, scratching or rubbing, and raw spots on the skin.

Horse Wrangler--(1) A hostler who keeps the string of extra saddle ponies that accompanies every cattle drive or used during roundup. He keeps them from straying and has them ready when they were needed (southwestern United States). (2) The rider on horseback who accompanies the rodeo rider and keeps the bucking broncho from injuring the contest rider before and after the riding has been done. (3) A person who works with horses during the breaking period.

Horse-biting Louse--Bovicola equi, family Trichodectidae; an insect pest of horses, mules, and donkeys that bites the skin, causing irritation.

Horsefly--In a broad sense, any member of the family Tabanidae, but usually restricted to the subfamily Tabaninae.

Horseguard--Bembix carolina, family Sphecidae; a black-and-yellow sand wasp found in southern United States where there are horses or cattle. It preys upon horseflies and bottlefiles, which it feeds to its larvae.

Horsemanship--The ability to show a high degree of skill in handling horses.

Hoss--(slang) Horse.

Host--Any organism, plant or animal, in or upon which another spends part or all of its existence, and from which it derives nourishment and or protection.

Host Specific--Designating a parasite that can live in or on only one host, to which it is therefore said to be specific.

Hot--(1) Designating a horse with a bad disposition. (2) Designating a fruit, such as a pepper, that has a pungent, strong, lasting flavor. (3) Designating weather. (4) Designating manure that heats upon decomposition. (5) An animal feed that contains a high percentage of concentrate or a feed containing a high level of salt.

Hot Carcass Weight--The weight of a carcass immediately after slaughter before the carcass has had time to age and shrink. See Cold Carcass Weight, Shrinkage, (6).

Hot Iron--The heated iron rod or stamp with a handle used in branding cattle, etc.

Hot Manure--Fresh manure that is going through the process of heating due to fermentation. Horse manure is designated as one of the hot manures. Cow manure is one of the cold manures. See Cold Manure, Cow Manure, Horse Manure.

Hot-blooded--(1) Designating a horse that has some Thoroughbred or Arab blood. (2) Designating a horse that is nervous and at times even vicious. See Cold-blooded.

Hothouse Lamb--A lamb that is dropped in the fall or early winter and is marketed at an age of six to twelve weeks. These are usually sold in periods before the Christmas or Easter holidays to take advantage of higher prices.

Hotis Test--A test for the rapid detection of certain microorganisms in raw milk.

House Bee--A young worker bee, one day to two weeks old, that works only in the hive.

Hover--(1) The sheet metal canopy surrounding a heat source under which incubator chicks are kept warm. (2) To cover chicks, as a hen hovers her chicks.

HQB--High-quality beef.

Humerus--The large bone of the pectoral limb located between the elbow and shoulder joints.


Hump Up--The attitude an animal takes in order to expose less body surface to rain, wind, cold, etc.: to pull the feet together and push the back up.

Hunter--A riding horse of quality conformation and size, especially adapted for the chase and riding to hounds; a Thoroughbred type of breeding, about 16 hands high.

Hurdle--A board made of plywood usually around 3 feet wide and 3 feet long that is used to herd pigs.

Hurdle System--A term sometimes applied to the method of handling sheep by means of a wolf-proof fence.

Husbandry--In its earlier usage, the skill, or art, of tillage, crop production, and rearing of farm animals. Today the word is occasionally used as a synonym for farming. More commonly used in combination, as animal husbandry and poultry husbandry, embracing the art, science, processing, and business of production.

Hutch--A boxlike cage or pen for a small animal; e.g., a rabbit hutch.

Hybrid--(1) An animal produced from the crossing or mating of two animals of different breeds. (2) A plant resulting from a cross between parents that are genetically unlike; more commonly, in descriptive taxonomy, the offspring of two different species.

Hybrid Bees--The offspring resulting from crosses of two or more selected inbred lines (strains) of bees; the offspring of crosses between races of bees.

Hybrid Chick--Chicks that result from crossing two or more inbred lines of the same or different breeds, varieties, or strains.

Hybrid F1--Plants of a first-generation hybrid of two dissimilar parents.

Hybrid vigor, insect or disease resistance, and uniformity are qualities of this generation. Seed from hybrid plants should not be saved for future planting. Their vigor and productive qualities are only in the original hybrid seed.

Hybrid Vigor--The increase of size, speed of growth, and vitality of a crossbreed over its parents. See Heterosis.

Hybridization--The production of hybrids by natural crossing or by manipulated crossing.

Hybridize--To create a hybrid.

Hydatid--The larval stage of the dog tapeworm, Echinococcus granulosus, which usually develops in the liver and lungs of people, cattle, swine, goats, sheep, and some other mammals. Hydatids are cysts containing the larvae. They may develop to a very large size, displace parts of the organs in which they grow, and cause a disease known as hydatid disease, or echinococcosis.

Hydrocyanic Acid--HCN; one of the most valuable and widely used of the fumigants. Except that it is highly toxic to people, it approaches the ideal in a fumigant. It is found in some plants, particularly sorghums, and may under certain conditions cause poisoning and death to animals. Sometimes called prussic acid.

Hydrogen Peroxide--A chemical substance often used as a bleach to remove color. It is used also in medicine and surgery as an antiseptic agent and as a cleansing agent in mouthwashes, toothpastes and powders. Its antiseptic and cleansing action is due to the fact that it gives off sufficient oxygen to destroy bacteria.

Hydrogenated Lard--Usually, steam-rendered lard to which extra atoms of hydrogen have been added. It is bland, has a high smoke point, is resistant to rancidity, and is whiter than common lard.

Hydrogenated Oils--Oil hardened by treatment with hydrogen in the presence of nickel. Cottonseed, corn, and wheat oils are commonly hardened and used in cooking fats.

Hydrophobia--Literally, fear of water; commonly refers to rabies, which is a misnomer. Rabid animals are not necessarily afraid of water; they often have difficulty drinking water due to paralysis of the tongue. See Rabies.

Hygiene--The science of health; the rules or principles of maintaining health in people and animals; sanitation.

Hyperemia--Excess blood in any part of the body.

Hyperesthesia--Excessive sensitivity of a part of the body to touch or pressure.

Hyperglycemia--An above-normal blood sugar level. See Hypoglycemia.

Hyperimmune--Designating the state or quality of having a high degree of immunity produced by repeated exposure to the same disease agent.

Hyperimmunization--Process of increasing the immunity of an animal by increasing injection of an antigen, subsequent to the establishment of an initial immunity; enhanced immunity.

Hyperparasite--An organism that is parasitic on another parasite.

Hyperphagia--Excessive hunger.

Hyperpituitarism--A condition brought about by excessive production of one or more hormones by the pituitary gland, causing abnormal or excessive growth, as in gigantism.

Hyperplasia--An increase in the number of cells in a tissue or organ.

Hypersaline--Term to characterize waters with salinity greater than 4.0 percent due to land-derived salts.

Hypersensitivity--The violent reaction of an organism to attack by a pathogen, a condition in which the response to a stimulus is unusually prompt or excessive in degree.

Hypersusceptible--Designating a condition of abnormal susceptibility to infection, or to a poison, to which a normal individual is resistant.

Hyperthyroidism--A condition of humans and lower animals in which the thyroid gland secretes excessively; characterized by rapid tissue change and restlessness. See Hypothyroidism.

Hypertrophy--(1) Pertaining to waters of very high nutrient content. (2) Morbid enlargement or overgrowth of an organ or part due to increase in size of its constituent cells.

Hypocalcemia--A below-normal level of calcium in the blood.

Hypodermis--The layer of tissue below the dermis of the skin.

Hypoglycemia--A deficiency of sugar in the blood. See Hyperglycemia.

Hypomagnesemia--A deficiency of magnesium in the blood. See Grass Tetany.

Hypophysectomy--The surgical removal of the pituitary gland.

Hypophysis--Another term for the pituitary gland, a structure located on the underside of the brain and embedded in the sphenoid bone.

Hypothyroidism--A condition of humans and animals in which the thyroid gland secretes inadequately; characterized by cretinism. See Goitrogen, Hyperthyroidism.

Hysterectomy--(1) Technique used in some Specific Pathogen Free laboratories to remove unborn pigs from the sow. The entire uterus is removed with the pigs inside. This operation makes the sow useless, and she is slaughtered immediately after the operation. (2) Surgical removal of all or part of the uterus.


Ice Cream Species--An exceptionally palatable species of forage sought and grazed first by livestock and game animals. Such species are usually overutilized under proper grazing.

Ice Milk--A frozen product that resembles ice cream except that the fat content is lower and the milk solids-not-fat content is usually higher. It contains 3 to 4 percent fat, 10 to 15 percent milk solids-not-fat, about 15 percent sugar, and a stabilizer.

Icterus--(1) Jaundice. (2) In plants, a yellowing of the leaves due to cold, excessive moisture, or other climatic factors.

IDA--International Dairy Arrangement.

Identical Twins--Twins that develop from a single fertilized egg that separates into two parts shortly after fertilization.

Idiopathic--Designating a disease or condition with no apparent cause.

Imago--(Plural, imagoes or imagines) The adult stage of an insect.

Immobilization--The action of rendering an object immovable, as the immobilization of an injured limb in an animal to allow for healing.

Immunity--Having resistance to the action of something, such as a disease. It may be inborn, may result from exposure to a disease, from having had a disease, or from having received an injection of immune serum. Degree of immunity varies in each case. See Immunizing Agent.

Immunize--To render an animal resistant to disease by vaccination or inoculation.

Immunizing Agent--A substance that, when introduced into the body of an animal, will build up antibodies in the blood that will resist or overcome an infection to which most of the same genus or species are susceptible.

Immunoglobulins--Proteinlike materials produced in the body that inactivate or destroy antigens.

Immunology--Science or study of immunity and its factors.

Impaction--The lodgment of undigested food or other objects, such as hair, in the digestive tract. See Bezoar, Hair Ball, Hardware Disease, Stomach Ball.

Impaction of the Bowels--Constipation.

Implantation--The process whereby the mammalian embryo forms an attachment to the uterine wall.

Impotence--Temporary or permanent loss of reproductive power or virility.

Impregnate--To fertilize a female animal or flower.

Imprinting--A kind of behavior common to some newly hatched birds or newborn animals that causes them to adopt the first animal, person, or object they see as their parent.

In Foal--Designating a pregnant mare.

In Hand--Designating an animal under control or immediately available.

In Heat--Designating a female animal at a period when she will accept coitus with a male. Also called estrus. See Estrus.

In Season--(1) That part of the year when a product is normally harvested and, as a result, is cheaper, more plentiful, and more flavorful. (2) See Estrus, In Heat.

In Utero--Within the uterus.

In Vitro--In the test tube, outside the animal body. See In Vivo.

In Vitro Fertilization--Fertilizing an egg with sperm in a test tube or petri dish, then implanting the fertilized egg into the uterus. See Artificial

Insemination, Embryo Transfer.

In Vivo--In the living body. See In Vitro.

In-and-In Breeding--The breeding together of closely related plants or animals for a number of successive generations to improve or eliminate certain characteristics. Also called breed in and in, line breeding, inbreeding.

Inappetence--Lack of appetite. Inbred--(1) An individual with parents who show 50 percent or more of common ancestry in their pedigree. (2) The offspring produced by self-pollination in normally cross-pollinated plants. (3) Of, or pertaining to, a plant or animal produced by breeding between close relatives.

Inbreeding--The mating of very closely related animals such as mother and son, father and daughter, brother and sister. In experienced hands it can be used to selectively maintain certain desirable traits; if used improperly it can produce undesirable traits and downgrade stock.

Incidence--The number of new cases of a disease occurring in a given population during a specific period, divided by the total number of persons at risk of developing the disease during that same period.

Incision--A cut.

Inclusion--A nonliving substance or particle in a cell.

Incompatibility--A condition in either plants or animals in which the viable male gamete will not fertilize the viable female gamete.

Incomplete Dominance--A kind of inheritance where a gene does not completely cover up or modify the expression of its allele; also may be known as codominance or blending inheritance.

Incorporate--To mix pesticides, fertilizers, or plant residues into the soil by plowing or other means.

Incubator--An apparatus or chamber that provides favorable environmental conditions for the development of embryos, the hatching of eggs, or the growth of cultures.

Independent Culling Levels--Selection of culling based on cattle meeting specific levels of performance for each trait included in the breeder's selection program. For example, a breeder could cull all heifers with weaning weights below 400 pounds (or those in the bottom 20 percent of weaning weight) and yearling weights below 650 pounds (or those in the bottom 40 percent).

Index--A system for comparing animals within a herd, or area, based on the average of the group; usually the figure 100 is used for an average index; animals receiving an index of 100 or over are the top end while those indexing less than 100 are the bottom end.

Indian Cattle--See Zebu.

Indian Pony--(1) A small riding pony used by the Indians of southwestern United States, which originated from horses shipped by the Spaniards to Mexico in 1519. Many became wild and their offspring were captured by the Indians. They are the results of natural propagation rather than any selection or planned breeding. (2) Any piebald or pinto pony.

Indigestion--A condition of the digestive system of humans and animals in which the normal digestive process is halted or disturbed. There are many causes, such as infection, spoiled food, overeating, etc.

Indiscriminate Breeder--An animal that will breed with any animal of the same type and the opposite sex.

Individual Claiming Pen--On goat ranches, a pen in which an individual doe that has disowned her kid is kept until she reclaims her offspring.

Individual Drinking Cup--A type of stock-watering equipment in wide use in modern stanchion dairy barns whereby water is supplied by a cup at the stanchion for each individual cow.

Individual Farrowing House--A separate building or quarters equipped so that sows that are to farrow may be kept isolated in warm, clean, and quiet individual pens at farrowing time.

Inedible--A substance that is not fit for food, such as poisonous nuts and plants. Tough skins, seeds, and decayed spots of fruits and vegetables and bones of meat are considered inedible parts because they are not suitable for human consumption.

Inert Ingredient--A substance in a feed, pesticide, etc., that does not act as a feed, pesticide, etc. The substance may serve a purpose but is usually used as a filler, vehicle, etc.

Infect--To cause disease by the introduction of germs, parasites, or fungi. See Infection.

Infection--Invasion of the tissues of the body of a host by disease-producing organisms in such a way that injury results; the presence of multiplying parasites, bacteria, viruses, etc., within the body of a host. See Infestation.

Infection Stage--The period in the course of a disease during which the host responds, symptoms appear, and the disease develops.

Infectious--Designating a communicable disease.

Infectious Abortion--See Brucellosis.

Infectious Anemia in Horses--See Equine Infectious Anemia.

Infectious Bovine Rhinotracheitis (IBR)--A respiratory disease characterized by inflammation, edema, hemorrhage, and necrosis of the mucous membranes of the respiratory passages, and pustular lesions on the genital organs of both male and female animals.

Infectious Bronchitis of Chicks--A respiratory, viral disease characterized by sneezing, coughing, a peculiar breathing sound, nasal exudate, and watery eyes. Mortality rate is high in young chicks. See Bronchitis.

Infectious Coryza--A severe, catarrhal inflammation of the mucous membranes of the upper respiratory tract of poultry caused by Hemophilus gallinarum. Symptoms commonly include a nasal discharge, which becomes thick and sticky with an offensive odor; adjacent sinuses become filled with mucus that may change to a dry, cheesy form and cause bulging around the eyes. Affected fowls have difficulty in breathing, shake their heads frequently, are listless, have loss of appetite, and lose strength rapidly. Crowding, dampness, and lack of ventilation are predisposing factors. Also called roup, cold, rhinitis.

Infectious Diarrhea--See Calf Scours.

Infectious Disease--A disease caused by bacteria, protozoa, viruses, or fungi entering the body. It is not necessarily contagious or spread by contact.

Infectious Enteritis in Pigs--A group of enteritis conditions in pigs caused by Salmonella bacteria (Salmonella cholera suis) and/or a group of other pathogenic enteric organisms such as Spherophorus necrophorus, coccidia, and viruses. The conditions are characterized by diarrhea and frequently by the presence of blood in the stool.

Infectious Keratitis--(Bovine) A very common disease of cattle characterized by swollen, red, and congested eyelids, a watery discharge from the eyes which in time contains mucus and pus, cloudy eyeballs, and temporary or permanent blindness. The cause has not been established. Also called pinkeye, contagious ophthalmia in cattle, infectious conjunctivitis.

Infectious Laryngotracheitis--An acute, highly contagious viral disease of fowls characterized by respiratory distress, coughing, watery eyes, sneezing, shaking of the head, sitting with eyes closed, gurgling breathing sound, and a stretching of the neck while inhaling. Also called infectious tracheitis, flu.

Infectious Necrotic Enteritis--See Infectious Enteritis in Pigs.

Infectious Necrotic Hepatitis--An acute disease of sheep caused by Clostridium novyi in the presence of liver flukes. The onset is sudden and acute, and apparently healthy animals can be stricken and die overnight. Also called black disease.

Infectious Sinusitis--A viral disease of turkeys characterized by a clear discharge from the nostrils, followed by a foamy condition of the eyes that are closed or partially closed, labored breathing, and loss of weight. Also called swellhead, sinusitis.

Infective--Capable of entering and establishing itself in a host; able to infect a susceptible plant or animal.

Infertile--(1) Designating that which is incapable of reproduction; e.g., a barren female animal, a male animal with nonviable spermatozoa, an unfertilized egg, a flower that will not produce seed. (2) A soil so low or unbalanced in essential nutrients that it will not produce a profitable crop.

Infertile Egg--(1) An ovum that has not united with a spermatozoon to form a zygote, or fertilized egg, hence, incapable of embryonic development. (2) An egg produced by an unmated female; a market egg produced by an unmated hen.

Infest--To assail, attack, overrun, annoy, disturb; as ticks infest a cow, or as an insect infests a plant.

Infestation--(1) Act of infesting, or state of being attacked, molested, vexed, or annoyed by large numbers of insects, etc., as an animal may be subject to an infestation of parasites, such as fleas, ticks, mites, etc. (2) Presence of disease in a population of plants, or of pathogens in a position, as in soil or on seed surfaces, where they have the possibility of producing disease. (Not to be confused with infection, which can be applied only to living, diseased plants and animals.) See Infection.

Infiltration--The flow of a liquid into a substance through pores or other openings, connoting flow into a soil in contradistinction to percolation, which connotes flow through a porous substance.

Inflammation--The reaction of a tissue to injury that tends to destroy or limit the spread of the injurious agent and to repair to replace the damaged tissues. The tissue is infiltrated by white blood cells, is red from capillary expansion and hot to the touch.

Influenza in Horses--A highly contagious viral disease characterized by a high temperature, general ill health, coughing, and nasal discharge. Also called shipping fever, pinkeye of horses, horse flu.

Influenza in Swine--An acute, highly contagious, infectious disease caused by the bacterium Hermophilus influenzae suis and a filterable virus; characterized by high temperature, thumpy coughing, discharge from the eyes and nose, and listlessness. The death rate is low. Also called hog flu, swine influenza.

Infundibulum--The enlarged, funnel-shaped structure on the end of the fallopian tubes that functions in collecting the ova during ovulation.

Infuse--(1) To steep in liquid so as to extract useful qualities, as tea. (2) To inject or introduce a liquid or medicinal agent, as to infuse the udder with a drug.

Ingest--To eat, or take in food for digestion by way of the mouth.

Ingesta--Contents of the digestive tract. Includes feed, digestive juices, bacteria, etc.

Ingestive Behavior--The mannerisms or habits that an animal uses during the intake of food.

Ingluvies--The crop or craw of a chicken or other bird; also the rumen or first stomach of a ruminating animal, as a cow.

Inguinal Canal--The opening in the abdominal wall through which the testes pass from the body cavity into the scrotum.

Inhalable Particulates--Particulates less than 10 microns that are not filtered from the air, and consequently are inhalable into the upper respiratory system.

Inhalants--Medicinal preparations that are inhaled or drawn into the lungs.

Inheritance--(1) The transmission of genetic factors from parent to offspring. (2) The process or procedure of transferring property, both real and personal, from one generation to the next, either by will or by laws of descent and distribution.

Inherited Characteristic (Trait)--A character, the expression of which is determined by a particular gene or genes.

Inhibit--To suppress, prevent, hinder, restrain.

Inject--To introduce a substance into the body of an animal or plant by mechanical means.

Inner Cover--A cover used under the standard telescoping cover on a beehive.

Inoculation--(1) Introduction into healthy plant or animal tissue of microorganisms to produce a mild form of the disease, followed by immunity. (2) An introduction of nodule-forming bacteria into soil, especially for the purpose of nitrogen fixation. (3) Treatment of seed with bacteria that stimulate development of bacteria nodules on plant roots. Used on legumes such as peas and beans. (4) Bacteria supplied to legumes to "fix" nitrogen from the air. (5) A small amount of bacteria produced from a pure culture that is used to start a new culture.

Insect--An air-breathing animal (phylum Arthropoda) that has a distinct head, thorax, and abdomen. Insects have one pair of antennae on the head, three pairs of legs, and usually two pairs of wings on the thorax. The opening of the reproductive organs is near the posterior end of the body. They may be harmful or useful depending upon their habits. Some infest plants and animals, some are insectivorous, some pollinate plans, and some produce edible products.

Insect Control--The chemical or biological inhibition or killing of insect enemies.

Insect Enemy--(1) Any insect that is destructive or harmful to something desired by humans. (2) An insect, bird, mammal, etc., that preys on other insects.

Insect Growth Regulator--A chemical that interferes with the normal growth pattern of insects causing abnormal development and thus death. In the case of flies, it may be added to chicken feed, passing through the bird with the feces into the manure. Present in the manure, it kills house fly larvae soon after they hatch.

Insect Vector--An insect that carries a virus, bacterium, or the spores or mycelium of a pathogenic fungus and inoculates susceptible plants, animals, and humans.

Insecticide--A substance that kills insects by chemical action, as a stomach poison, contact poison, or fumigant.

Inseminate--To place semen in the vagina of an animal during coitus, or, in the practice of artificial insemination, to introduce semen into the vagina by a method other than coitus.

Inseminating Tube--A rubber, glass, or metal tube, usually with syringe attachment, used in artificial insemination to introduce the semen into the vagina of a female animal. Such instruments vary in character depending on the species being bred.

Inseminator--The technician, in the employ of an artificial breeder's unit, who brings the prepared semen to the farmer's herd and performs the technical service of inseminating the cows.

Insidious Disease--A disease that develops slowly in a stealthy, subtle manner over a long period of time.

Insipid--(1) Designating a flavor defect of cheese characterized by a lack of taste and odor. (2) designating any such flavor.

Insoluble--Not soluble; designating a substance that does not dissolve in another.

Insoluble Ash--That portion of milk ash that is not soluble in water.

Instar--An insect that is between the stages of its molting process.

Instinct--The ability of an animal based upon its genetic makeup to respond to an environmental stimulus; it does not involve a mental decision.

Instrumental Insemination--The act of depositing semen into the oviducts of a queen bee by the use of an instrument.

Insufflation--The blowing of a powder or vapor into a cavity for medication.

Insulin--The hormone from a part of the pancreas that promotes the utilization of sugar in the organism and prevents its accumulation in the blood.

Integrated Pest Management (IPM)--An ecological approach to pest management in which all available necessary techniques are systematically consolidated into a unified program, so that pest populations can be managed in such a manner that economic damage is reduced and adverse side effects are minimized.

Interaction--The process of chemicals being mixed together and having substantially different toxicity than the toxicities of the components. The chemicals may interact to increase or decrease toxicity. See Antagonism, Synergist.

Interbreeding--In livestock breeding, the breeding closely within a family or strain for the purpose of fixing type and desired characters.

Intercellular--Between cells.


Interdigital--Between the fingers, toes, or claws.

Interfering--The striking of the fetlock or cannon by the opposite foot that is in motion. This condition is predisposed in horses with base-narrow, toe-wide, or splay-footed standing positions.

Intergeneric Cross--A cross between species of different genera (rare).

Intermediate Host--An animal other than the primary host that a parasite uses to support part of its life cycle.

Intermingling Color--A coat color pattern of animals in which the separate colors merge where they meet. It is usually an objectionable color pattern.

Intermittent Attacks--The return of symptoms after a period without symptoms; e.g., recurrent attacks of malaria.

Intermittent Grazing--Grazing a pasture for indefinite periods with periods of rest between grazing.

Intermittent Parasites--Those parasites, such as mosquitoes or bedbugs, that approach the host only when in need of nourishment.

Intersex--Designating an organism that displays primary and secondary sexual characteristics intermediate between male and female.

Interspecific--Referring to events or relationships that occur between individuals of different species.

Interspecific Hybrid--Cross between individuals of different species. Taxonomically identified by listing both species separated by an x.

Interstitial--A term referring to the spaces (voids) between particles, as between sand grains.

Intestinal Bloat--Abnormal distention of the intestines with gas.

Intestinal Coccidiosis--See Coccidiosis.

Intestinal Worm--Any internal parasitic worm that inhabits the intestines.

Intestine--The part of the digestive tract between the stomach and anus.

Intoxication--The state of being poisoned or drunk.

Intra--A prefix meaning within, inside; as intrastaminal, inside the (ring of) stamens; intraspecific, within a species.

Intracellular--Within, inside of, a cell.

Intracellular Fungus--A fungus that occurs or grows within a cell.

Intracervical Method--A method of artificial insemination whereby semen is placed directly in the cervix or uterus and not in the vagina.

Intradermal--Within the layers of the skin.

Intradermal Tuberculin Test--A test used to discover tuberculosis in animals, which consists of injecting into the skin of the tail (caudal fold), or elsewhere, a minimum of concentrated tuberculin. If the animal is infected, 72 hours after the injection there will be a swelling at the point of injection.

Intramuscular--Within the muscles.

Intramuscular Injection--Injection of a substance into a muscle.

Intranasal Instillation--The placing of fluid or medicine inside the nose.

Intraocular Vaccination--In poultry, the placement of a vaccine directly into the eye.

Intraperitoneal--Within the cavity of the body that contains the stomach and intestines.

Intraspecific--Referring to events or relationships that occur between individuals of the same species.

Intraspecific Hybrid--Cross between individuals within the same species, but of different genotypes.

Intratracheal--Within the trachea, or windpipe.

Intrauterine--Within the uterus.

Intravenous--In, into, or from within, a vein or veins.

Introduced--Designating a plant, animal, disease, etc., that is not indigenous to an area, but is brought in purposely or accidentally.

Introducing Cage--Small wood and wire cage used to ship queen bees and also sometimes to release them into the colony.

Introgastric--In the stomach.

Introgression, Hybridization--Long-continued interspecific hybridization leading to an infiltration of genes from one specie into another.

Intromittent--Designating the use, in copulation, of the external reproductive parts of many male animals.

Invertase--Enzyme produced by bees that speeds inversion of sucrose to glucose and fructose.

Invertebrate--(1) Any animal with no spinal column. (2) Having no spinal column.

Inverted Nipple--A teat (usually refers to a sow's teat) that appears to be inverted toward the udder. The teat is nonfunctional.

Involution--The return of an organ to normal size after a time of enlargement, as in the case of the uterus after parturition.

Iodine--A trace element in soil, an essential element for the health of humans and animals. A deficiency causes goiter. It is readily absorbed by plants from soil and water, but it is not essential to plants.

Iodine Value--Sometimes referred to as iodine number, the measure of the degree of unsaturation of a fat by the extent of the uptake of iodine (the number of grams of iodine absorbed per 100 grams fat) by the unsaturated double bonds in the fatty acid chain. Hence, butter with an iodine value of 22 to 38 is more highly saturated than cottonseed oil with an iodine value of 104 to 114.

Iodized Salt--That salt prepared by mixing salt with potassium iodide in the proportion of about one part of iodide to 5,000 parts of salt.

Iodized salt is of value in the prevention of simple goiter, which is endemic in people and animals in certain parts of the United States.

Ion--An atom or a group of atoms carrying an electrical charge, which may be positive or negative. Ions are usually formed when salts, acids, or bases are dissolved in water. When common salt, sodium chloride, is dissolved in water, positive sodium ions and negative chloride ions are formed. See Anion, Cation.

Ion Exchange--The replacement, in a colloidal system, of one ion by another with a charge of the same sign.

Ionization--The process by which an atom becomes electrically charged, by the removal or addition of one or more of its extranuclear electrons, so that the electrical balance between the electrons and the protons within the atom's nucleus is destroyed. An atom with more than its normal complement of electrons has a negative charge; with less, it has a positive charge.

Ionophore--A feed substance or additive that makes the digestive processes in ruminants more efficient.

Iron--Fe; a metallic element essential to people, animals, and plants; very common in some minerals, most rocks, and all soils; an essential constituent of blood hemoglobin where it functions to transport oxygen.

Iron is specific for the treatment of anemia in animals. In plants, iron deficiency results in iron chlorosis.

Iron Gray--A coat color term for a horse that (a) in the United States, denotes a white coat with a high percentage of black hairs; (b) in England, a gray coat with reddish hairs throughout.

Irradiated--Designating a food or feed treated with ultraviolet light to increase the vitamin D content.

Irradiated Milk--Market milk treated with ultraviolet light so that the ergosterol is changed to vitamin D.

Irradiated Yeast--Yeast subjected to ultraviolet rays in order to increase its antirachitic potency. It is used as an ingredient in feeds for its vitamin D and B-complex content.

Isinglass--(1) Very pure gelatin prepared from the air bladders of fishes, especially sturgeon; used as a replacement for gelatin in jellies and puddings, and as a clarifying agent. (2) Mica in sheets.

Islet (Island) of Langerhans--The tissue lying in the framework of the pancreas that secretes the hormone insulin.

Isogamy--Morphological similarity of fusing gametes.

Isolate--To place an animal in confinement away from other animals to prevent breeding or spread of disease.

Isotopes--Elements having an identical number of protons in their nuclei, but differing in the number of their neutrons. Isotopes have the same atomic number, differing atomic weights, and almost but not quite the same chemical properties. Different isotopes of the same element have different radioactive behavior.

Isthmus--(1) In biology, a narrow piece of tissue that connects two larger parts; the part of the Fallopian tube between the ampulla and the uterus. (2) In poultry, that part of the oviduct where the two shell membranes are added to the egg.

Italian Bees--A race or variety of honeybee that originated in Italy and has become widely dispersed and crossbred with other races.

Itch Mite--Sarcoptes scabiei, family Sarcoptidae; a mite that infests humans and other animals. In humans it causes itch and in animals, mange.

-itis--A suffix denoting inflammation, as dermatitis, inflammation of the skin; tonsillitis, inflammation of the tonsils.

Ivermectin--A broad-spectrum drug that can be injected into livestock for control of both internal and external parasites. It is reputed to kill adult and immature roundworms and lungworms, and external grubs, lice, and mites.


Jack--(1) The male, uncastrated ass. See Jenny. (2) A mechanical, hydraulic device used for lifting heavy objects. (3) See Bone Spavin.

Jackass--See Jack.

Jaundice--A syndrome seen in animals and people characterized by excess bile pigment in the blood and deposition of bile pigments in the mucous membranes and skin resulting in a yellow or yellowish-orange complexion. Also called icterus.

Jejunum--The part of the small intestine between the duodenum and the ileum.

Jenny--A female donkey. Also called jennet.

Jerk--To cut meat, usually beef, into long, thin strips, and dry it in the sun.

Jerked Beef (Jerky)--Beef that has been naturally dried. Also called charqui. See Jerk.

Jersey--A widely used breed of dairy cattle from the Isle of Jersey. They are of extreme dairy type, solid fawn, red, or nearly black, and their milk has the highest butterfat content of any breed. Weight at maturity varies form 800 to 1,000 pounds.

Jersey Buff--A small, well-fleshed, buff-colored variety of turkey. It is a recently developed variety from New Jersey, United States.

Jet Black--A horse color that is a shiny black.

Jib(ber)--A balky horse.

Jig--(1) An uneven gait of a horse, closely associated with prancing and weaving. (2) A device built to aid in construction; used to make duplicate cuts, holes, etc.

Jimmies--A condition of sheep resulting from feeding on the bulbs of cloak fern (Notholaena sinuata), family Polypodiaceae. Affected animals arch their backs, walk with a stilted movement of the hind legs, breathe rapidly, and tremble.

Jockey Stick--A stick fastened to the hame of a broken horse and to the bit of a green horse to prevent them from crowding and to keep the green horse in position while being broken.

Johne's Disease--A chronic, infectious disease of cattle, sheep, and goats caused by Mycobacterium paratuberculosis. It causes loss of condition, unthriftiness, persistent diarrhea, reduction of milk yield, alternate refusal to eat and ravenous eating, general debility, prostration, and finally death. Also called chronic bacillary diarrhea, pseudotubercular enteritis, paratuberculosis, chronic bacterial dysentery.

Joint--(1) the point or place at which two bones meet: the articulation between the two bones. (2) The pint or meeting of two pipes. (3) A general term for a cut of meat (England). (4) See Node.

Jowl--(1) The cheek of a pig. (2) Meat taken from the cheeks of a hog.

Judas Goat--A trained goat used by a slaughterhouse to lead sheep to the killing pens.

Jug--(1) A small claiming pen where ewes with newborn lambs are kept until the ewe has nursed and claimed her young. (2) A glass bottle holding one-half gallon or a gallon, used to bottle cider, syrup, molasses, etc. (3) A deep vessel of earthenware narrowed to a neck, which is frequently fitted with a finger handle for carrying. (4) A small pen, part of a corral, used to funnel animals down a narrow alley (chute) to facilitate sorting, loading, or catching; used primarily with cattle.

Jughead--A horse with poor characteristics, little sense, and not amenable to training.

Julep--(1) Ancient Arabian name for a cooling drink containing muscilage, opium, etc. (2) An American drink.

Jumbo Hive--A beehive 21/2 inches (5.35 centimeters) deeper than standard Langstroth hive.

Jumper--(1) A class of horse, usually a Thoroughbred, able to jump high hurdles and used in shows. (2) Any animal with a tendency to jump over fences and therefore somewhat difficult to restrain.

Junior Calf--In stock judging, a beef or dairy animal that was born after January 1 of the year it is shown.

Junior Champion--In stock judging, the best animal of the younger classes selected from the first prize winners.

Junior Spring Pig--In stock judging, a swine that was farrowed on or after March 15 of the year it is shown.

Junior Yearling--In stock judging: (a) a beef animal calved between

January 1 and April 30 of the preceding year; (b) a dairy animal calved between January 1 and June 30 of the preceding year; (c) a swine farrowed between March 1 and August 31 of the preceding year.

Juvenile--(1) Coming to the surface for the first time; fresh, new in origin; applied chiefly to gases and waters. (2) Pertaining to the young of any animal.

Juvenile Hormone--The hormone, secreted by the corpora allata, that maintains the immature form of an insect during early molts.


Kak--A kind of saddle bag.

Karakul--A small, light-shearing breed of broadtailed sheep from west-central Asia, bred especially for the lambskins used in the fur pelt industry.

Karatin--Protein found in hair, feathers, horns, and hoofs.

Karyotype--A picture or diagram of the chromosomes of a particular cell as they appear in the metaphase of mitosis arranged in pairs by size and location in the centromeres.

Katabolism--See Catabolism.

Ked--See Sheep Ked.

Keel--(1) The part of a fowl's body that extends backward form the breast. Also called breastbone. (2) The two front, united petals of a pealike flower. (3) In ducks, the pendant fold of skin along the entire underside of the body. (4) In geese, the pendant fold of flesh from the legs forward on the underpart of the body. (5) A central dorsal ridge, like the keel of a boat. (6) The two anterior united petals of a papilionaceous flower.

Keel Disease--See Avian Typhoid.

Keeled--Of, or pertaining to, a ridge (like the bottom of a boat) on an animal or plant part.

Keeping--Designating the storage qualities of a product.

Keet--The young guinea fowl.

Keratin--A complex protein distinguished by high insolubility. It is the substance of which hair, horns, claws, and feathers are composed.

Keratitis--An inflammation of the cornea of the eye. Ketone Bodies--Chemical substances such as diacetic acid, hydroxybutyric

acid, and acetone, produced in the liver of animals. Excessive amounts of such substances in the body result in ketosis. When ketones are eliminated in excessive amounts in the urine, the condition is called ketonuria, acetonemia.

Ketosis--A metabolic disease characterized by loss of appetite, markedly poor condition of skin and flesh, digestive disorders, sometimes nervous symptoms, and foul-smelling milk. It often occurs as a primary metabolic disturbance in cattle, in pregnancy disease of sheep, in diabetes, and certain other conditions. Also called acetonemia, false milk fever, chronic milk fever, acetonuria.

Kicking Hobble--A rope or strap fastened to the rear legs or feet of a horse, ass, or cow to prevent kicking.

Kicking Strap--A strap fastened to the crupper strap of the harness in breaking colts. It extends down each side of the shaft of the carriage and is used to prevent kicking.

Kid--(1) A young goat. (2) To give birth to a kid.

Kid Crop--The number of kids produced by a given number of does, usually expressed in percent of kids weaned of does bred. Kid House--A small structure designed to give shelter to a newborn kid. The doe is staked so that it cannot abandon its kid.

Kid Mohair--The finest quality of Mohair, taken from young goats.

Kidney--A bean-shaped organ of humans and certain lower animals that excretes urine. The lamb kidney is edible, and kidneys from other animals are converted into edible products.

Kidney Faller--A horse that collapses in the hindquarters when it walks.

Kidney Knob--The fat on a beef carcass that surrounds the area where the kidneys were removed.

Kidney, Pelvic, and Heart Fat--The internal fat of an animal carcass. Specifically, the fat that surrounded the kidneys, pelvic cavity, and heart within the body cavity.

Killing Cattle--Cattle, usually grass-fattened on a ranch or range, of sufficiently good flesh and finish to be slaughtered profitably.

Killing Floor--The place in a slaughterhouse where a stunned animal is killed, bled, skinned, eviscerated, and where the carcass is split, washed, and wrapped.

Kind--(1) All the plants of the same type, accepted as a single vegetable or fruit, as tomato, cabbage, bean, apple, peach, etc. (2) A species, as a cow, sheep, etc.

Kind of Animal--An animal species or species group such as antelope, cattle, deer, elk, goats, horses, etc.

Kindle--(1) To give birth to a litter of rabbits. (2) A young rabbit.

Kine--Cows or cattle.

King Bee--Before the seventeenth century, it was popularly believed that the queen bee was a male who ruled the hive. See Queen Bee.

Kip--A hide taken from a very young calf.

Kippered--Lightly salted and smoked fish.

Kleins' Disease--See Avian Typhoid.

Knee--(1) The joint between the hip and the ankle in humans and quadrupeds (hind leg); in birds, the tarsal joint. (2) The carpal joint (foreleg). (3) The spurlike, root growth of the baldcypress that develops when the tree grows in a swamp.

Knee Banger--A horse that strikes its knees with the opposite front foot while walking or running.

Knee Spavin--A chronic inflammation of the small bones of the carpal joint of horses, characterized by lameness, bony enlargement, a dragging of the toe of the affected leg, and a fusion of the carpal bones.

Knob--(1) A rounded hill or mountain, especially an isolated one. Local in the United States South. (2) The horny protuberance at the juncture of the head and upper bill in African and Chinese geese. (3) A deformity growth on the breastbone, usually at the front, sometimes found in chickens and turkeys; a defect. (4) The rounded protuberant part of the skull in crested fowl.

Knock-kneed--An undesirable conformation or weakness of the front legs of horses in which the legs are not straight due to the knees coming too close together.

Knuckle--The joint of two bones often used in making soup stock.

Koi--Fish of the Carp family that are raised because of their colorful appearance.

KPH--See Kidney, Pelvic, and Heart Fat.


Labium--(1) The posterior mouthpart or lower lip of an insect. (2) A lip or liplike organ. (3) The folds of skin of the vulva.

Labored Breathing--Any abnormal form of breathing in an animal in which the animal appears to be straining or working excessively hard to get air into or out of the lungs. Such breathing may be shallow and rapid, deep and slow, or deep and rapid.

Labrum--The anterior mouthpart or upper lip of an insect.

Laceration--A wound, especially one caused by tearing.

Lactate--To produce and secrete milk.

Lactation--The period of milk secretion. Usually begins at parturition and ends when offspring are weaned, or, in the case of dairy cattle, the animal is dried up.

Lactic Acid--A hydroxypropionic acid; a syrupy liquid generated by the natural souring of milk or the induced fermentation of various food products, such as sugars, starches, etc., by any of various organisms. It is used in cultured milk products, pickles, soft drinks, etc.

Lactic Fermentation--The preserving process that occurs in the making of sauerkraut, dill pickles, fermented string beans, silage, etc.

Lactic Former--Any organism that changes sugars into lactic acid, as Lactobacilus plantarum.

Lactiferous--Producing a milky substance, such as the nearly ripe poppy capsule.

Lactogen--The specific hormone that initiates and maintains lactation. Also called gelactin.

Lactogenic Hormone--Any hormone that stimulates lactation, especially prolactin.

Lactoglobulin Fraction--That small portion of milk protein that contains more sulfur and less phosphorus than casein.

Lactometer--An instrument that determines the density of milk. It acts as a specific gravity indicator, from which information on the percentage of milk solids may be calculated.

Lactose--[C.sub.12][H.sub.22][O.sub.11]; a white crystalline disaccharide made from whey and used in pharmaceuticals, infant foods, bakery products, and confections; also called milk sugar.

Lagoon--(1) Body of shallow water, particularly one possessing a restricted connection with the sea. (2) Water body within an atoll or behind barrier reefs or islands. (3) A body of water more than 1 meter deep established for anaerobic decomposition of organic wastes.

Lagoon, Aerobic--Lagoons larger than one-half acre and deeper than three feet must be stirred mechanically to supply oxygen for aerobic stabilization of wastewater sludge. See Lagoon, Anaerobic.

Lagoon, Anaerobic--A wastewater sludge treatment process larger than one-half acre and deeper than three feet that is not aerated mechanically. See Lagoon, Aerobic.

Lamancha--A breed of dairy goats developed by crossing several pure bred breeds. The breed is noted for their very small, short ears. They may be any color.

Lamarckism--A belief, named after French naturalist Jean Baptiste de Lamarck (1744-1809), that acquired characteristics can be inherited. Now proved false.

Lamb--(1) The young of sheep: specifically, (a) a young ovine that has not yet acquired the front pair of permanent incisor teeth; technically, (b) in stock judging, a sheep born in the same calendar year as shown. (2) To give birth to a lamb.

Lamb Bar--Apparatus for communal feeding of lambs and kids consisting of a container for milk with several artificial teats set into it.

Lamb Crop--The number of lambs produced by a given number of ewes, usually expressed in percent of lambs weaned of ewes bred.

Lamb Flock--In stock judging, one ram lamb and three ewe lambs.

Lamb Hog--A male lamb from weaning time until it is shorn.

Lamb Riblet--A retail cut of lamb for stewing or braising that consists of thin slices of breast along with ribs.

Lamb Shank--A retail cut of lamb for stewing or braising which consists of the shank. Also called trotter.

Lamb's Wool--Short wool taken from lambs not over seven to eight months old, although some wool which is taken from lambs of twelve to fourteen months of age is also graded as lamb's wool. It is soft and has less felting properties than sheep wool.

Lambing--The dropping, or birth, of lambs (in sheep husbandry, a time or regular event in management). See Lambing Time.

Lambing Ground--Range reserved for grazing during the lambing period.

Lambing Loop--A length of smooth or plastic-coated wire used as an aid in difficult lambing.

Lambing Pen--A specially equipped, isolated pen in the sheep barn in which a ewe is placed just before she gives birth to her young.

Lambing Percentage--The number of lambs produced per 100 ewes.

Lambing Range--See Lambing Ground.

Lambing Shed--A shed or barnlike building in which ewes are placed just before they give birth to lambs.

Lambing Time--The season of the year, usually late winter or early spring, when sheep produce their young.

Lamella--(Biology) One of the layers of a cell wall; a thin layer in a shell, like a leaf in a book.

Lameness--Any soreness, tenderness, or unsoundness that is indicated by the unnatural action of feet or legs of animals.

Laminated Wood--A piece of wood built up of layers of wood that have been joined with the grain parallel, either with glue or with mechanical fastenings. The term is most frequently applied where the layers are too thick to be classified as veneer.

Laminitis--Inflammation or congestion of the sensitive tissues, the laminae, which lie immediately below the outer horny wall of a horse's foot. It is characterized in the acute stage by expression of pain, standing still, dilated pupils, bright red membranes of the eyes, and rapid breathing. The pulse at first is very strong and fast but becomes weaker and the temperature is above normal. Among the various causes are: ingestion of excessive amounts of grain (grain founder), drinking cold water while overheated, concussion during hard fast road work or from long truck or train rides, toxemia as a result of pneumonia or metritis, etc. Some cases may be an allergic reaction. Grain founder is usually the most common type. Also called founder. See Founder.

Lampas (Lampers)--A swelling of the mucous membranes in the hard palate immediately behind the upper incisors of the horse. Also called palatitis. See Palatitis.

Land--(1) The total natural and cultural environment within which production must take place. Its attributes include climate, surface configuration, soil, water supply, subsurface conditions, etc., together with its location with respect to centers of commerce and population. Oyster beds and even tracts or bodies of water, as where valuable fishing rights are involved, may be regarded as land. It is often convenient, in fact, to regard land as synonymous with all that nature supplies, external to humans, which is valuable, durable and appropriable, thus including, e.g., waterfalls and other sources of waterpower. (2) In a broad legal sense, any real part of the surface of the earth, including all appurtenances, anything in, on, above, or below the surface. (3) In plowing, a plowed or unplowed space between two furrows. (4) The total width of a strip of land tilled by a farmer, or some designated width, as a perch, 16 1/2 feet. Also called a stitch. (5) Soil. (6) A natural part of the earth's surface characterized by any single factor, or combination, of topography, climate, soil, rocks, vegetation; the natural landscape. (7) Pertaining to agriculture, those areas actually in use or capable of use for the production of farm crops and livestock.

Landrace--A popular, white hog characterized by large drooping ears, a long snout, and good mothering ability.

Lane--A passageway from barnyard to pasture or field areas; a narrow road confined between fences.

Langstroth Frame--A minister from Pennsylvania, L.L. Langstroth, who patented the first beehive incorporating bee space thus providing form removable frames. The modern hive frequently is termed the

Langstroth hive and is a simplified version of similar dimensions as patented by Langstroth. The standard frame measures 91/8 by 175/8 inches. See Bee Space.

Lanolin--The fatty substance removed from sheep wool when it is scoured and cleaned. When refined, it is used extensively in cosmetics and provides a nontoxic carrier for applying plant regulators or other chemicals to the surface of plants.

Lapse Rate--See Adiabatic Lapse Rate.

Lard--The fat rendered from fresh, clean, sound, fatty tissues of hogs in good health at the time of slaughter. It is used as a food product for frying, shortening, etc. In recent years, lard has been largely replaced by vegetable oils.

Lard-type Hog--An antiquated term denoting a fat type of hog that was developed in the United States. Most of the breeds common in the United States were originally classified as this type. It was especially adapted to a high degree of quick fattening, with heavy back and thick sides. See Bacon-type Hog, Meat-type Hog, Fat-type Hog.

Lareat--See Lariat.

Large Egg--A United States grade of eggs having a minimum net weight of 24 ounces per dozen.

Large Roundworm--A common name referring to various species of roundworms belonging to the family Ascaridae, which parasitize humans, domestic livestock, and birds. The scientific names of these large roundworms are: Parascaris equorum (equines); Neoascaris vitulorum (cattle); Ascaris lumbricoides (swine, humans); Toxocara canis, T. mystax, Toxascaris leonina (dogs and cats); Ascaridia galli, A. columbae, A. numidae (domesticated birds).

Lariat--Rawhide, horsehair, or hemp rope, generally 35 to 45 feet long and arranged in a coil on the saddle. Used to lasso livestock for branding or restraining purposes. See Lasso.

Larva--The immature insect hatching from the egg and up to the pupal stage in orders with complex metamorphosis; the six-legged first instar of mites and ticks.

Larvicide--A chemical used to kill the larval or preadult stages of parasites.

Larynx--The upper portion of the windpipe (trachea).

Lasso--(1) To throw a lariat in such a manner as to catch an animal by the horns, neck, or legs in the loop at the end, generally for restraining purposes. (2) A rope or line with a running loop used for catching animals. Lee Lariat.

Latent--Designating an infection that is present but which is not manifest in the host under consideration. See Dormant.

Lateral--(1) A directional or positional term meaning away from the middle or toward the side. (2) A part of a system that branches out from the main body of the system, such as the tile lateral drain that connects to a main drain in a drainage system. (3) A branch or twig of a tree.

Lateral Canter--A horse's gait characterized by a simultaneous beat of corresponding front and rear feet, as opposed to diagonal front and rear feet.

Lateral Lacunae--The two grooves that border the horny frog of a horse's hoof.

Lateral Ringbone--A bony growth on the side of the pastern bone in a horse's leg. See Ringbone.

Lathyrism--A disease of animals caused by eating roughpea (Lathyrus spp.) which is high in selenium.

Lavage--The process of washing out the stomach or intestines. In gastric lavage, a double-way tube is passed down the esophagus into the stomach.


Laxative--A mild medicine used to relieve constipation.

Lay--To ovulate and deposit an egg or eggs produced within the female generative organs, as a hen lays eggs.

Layer--(1) A mature female fowl that is kept for egg-laying purposes, especially one in current egg production. (2) A course or stratum, as a layer of sand. (3) A plant twig or shoot, tied down and partially covered with earth, so that it can take root while remaining unsevered from the parent stock. (4) To reproduce by layerage.

Laying Ability--The ability of a particular hen to produce eggs, commonly measured by the number of eggs produced in a given time, as in a month or year. It is largely determined by five inherent qualities: (a) earliness of sexual maturity, (b) persistency of production, (c) intensity (or rate) of production, (d) broodiness, and (e) pauses.

Laying Mash--Any of several special feed preparations, conducive to egg production, that is fed to laying flocks of poultry.

Laying Nests--A series of connected cubicles in which hens lay eggs. They are usually made of metal to help keep down problems with parasites.

Laying Worker--A worker bee that lays eggs that produce drones. Laying workers usually develop in queenless colonies.

[LC.sub.50]--See Lethal Concentration.

[LD.sub.50]--See Lethal Dose 50.

Lead Cattle--The cattle at the head of a moving herd.

Lead Line--A bluish line at the margin of the gums of an animal that indicates chronic lead poisoning, usually as a result of ingestion of paint or spray materials. See Lead Poisoning.

Lead Poisoning--Poisoning that results from ingestion of lead, usually of paint containing lead. it is characterized (a) in horses by convulsions, partial paralysis, colic, roaring, thirst, and increased urination; (b) in cattle, by staggering, impaired vision, and unusual postures. See Lead Line.

Leader--(1) The main or dominant stem of a plant. (2) The front animals of a tandem hitch.

Lean--(1) A piece of meat that consists largely of muscles lacking in fat or the proper proportion or distribution of fat. (2) Designating an animal lacking in condition of flesh or finish.

Lean to Fat Ratio--The amount of lean meat in a carcass compared to the amount of fat.

Leather--(1) The cured, tanned skins of animals, especially of the bovines. (2) A pad of leather placed between the shoe and the foot of a horse with a sensitive sole. (3) See Fruit Leather.

Lecithin--One of a group of lipids known as phospholipids. Abundant in brain tissue and egg yolk. Obtained from peanuts, corn, and soybeans for commercial use (as an emulsifier in such products as chocolate).

Lectins--A group of protein substances, natural antibodies; agglutinins for type A red blood cells. Lectin may be obtained from lima beans.

Leg--(1) Any of the limbs of animals that support and move the body, such as foreleg, front leg, hind leg. (2) A cut of meat which is that portion of the leg between the knee and ankle, such as a chicken leg, leg of lamb. (3) To haul or drag a sheep from the pen to the shearing board by a hind leg.

Leg Conformation Grade--A grade assigned to the leg of a lamb or lamb carcass to indicate thickness of muscling. It is used in determining yield grade.

Leg of Lamb--A cut of meat comprising that section of the leg in which the shank of meat is tucked into a pocket made under the vellum on the inside of the leg of a lamb.

Leg of Mutton--A retail cut of meat from a mature sheep that comes from the same portion of the carcass as the leg of lamb.

Leggy--(1) Designating a plant which has unusually long stems. (2) Designating an animal, usually very young, as a colt, whose legs are dis-proportionally long in relation to its body size.

Leghorn--An egg-type breed of domestic chickens of the Mediterranean class characterized by yellow skin, nonfeathered shanks, nervous disposition, fast feathering, and relative nonbroodiness. Mature males weight about 6 pounds, mature females about 4 1/2 pounds. The eggshell is white. The Single Comb White Leghorn, the outstanding variety of the breed, universally raised, is one of the world's leading and most highly developed breeds for efficient production of market eggs.

Legume Silage--Legume crops, such as alfalfa and Ladino clover, which make satisfactory silage, especially if mixed with grasses and put into the silo in proper condition.

Leishmaniasis--Any disease due to infection with microscopic protozoan parasites of the genus Leishmania.

Leppies--Orphan calves (southwestern United States).

Leprosy--A chronic, transmissible disease due to a specific bacterium, Mycobacterium leprae.

Leptospirosis--A disease of animals and occasionally of humans caused by species of the genus Leptospira. In dogs, it is caused by L. canicola and is characterized by loss of appetite, depression, fever, thirst, vomiting, loss of weight, nephritis, and death. In cattle, it is caused by L. pomona or by L. icterohemorrhagiae and is characterized by loss of appetite, fever, jaundice, abortion, and sometimes death.

Lesion--Injury or diseased condition of tissues or organs.

Let Down Milk--To accelerate greatly the secretion of milk at the regular milking time. The milk glands of the udder are stimulated by massaging the teats and udder or by the sucking of the calf. There is also some influence of stimulating hormones, the most important being prolactin. See Hold Up Milk.

Lethal--Deadly; causing death, as a lethal dose.

Lethal Characters--See Lethal Gene.

Lethal Concentration (LC)--The lethal concentration (written as [LC.sub.10] or [LC.sub.50] or [LC.sub.100] or any percentage) median is the parts per million (ppm) or parts per billion (ppb) of toxicant in water or air that kills 10, or 50, or 100 percent, respectively, of the target species in a 24hour period. Usually used for fish. See Effective Concentration, Lethal Dose.

Lethal Dose--The lethal dose (written as [LD.sub.10], [LD.sub.50], [LD.sub.100], or any percentage) median is the milligrams of toxicant per kilogram of body weight that kills 10, 50, or 100 percent of the target species. See Effective Concentration, Lethal Concentration.

Lethal Gene--A gene that can cause the death of an individual when it is allowed to express itself.

Letting Down--The adjusting period, with some loss of flesh, which takes place when beef cattle are changed form heavy, drylot feeding to open pastures or range feeding.

Leucocyte--The white cells of the blood that destroy disease germs and help remove foreign matter from the bloodstream or tissue. Found predominantly in pus.

Leucocytozoon Infection--An acute and highly fatal disease of ducklings and poults caused by protozoan parasites: Leucocytozoon simondi in ducks, L. smithi in turkeys. Symptoms are loss of appetite, lethargy, thirst, rapid and labored breathing, excitement, loss of equilibrium, convulsions, coma, and foamy discharge from the nose and mouth.

Leukemia--Cancers of the blood-forming organs, characterized by abnormal proliferation and development of leukocytes (white blood cells) and their precursors in the blood, lymph, bone marrow, and lymph glands.

Leukocytes--White blood cells.

Leukosis--Avian leukosis complex.

Levorotatory Honey--A honey that does not contain honeydew. It rotates to the left the beam of polarized light passed through it in a special optical tube. See Dextrorotatory Honey.

Levulose--Noncrystallizing sugar of honey that darkens readily if honey is overheated.

Ley--A temporary pasture. Also spelled lea, a meadow (obsolete).

Leydig Cells--Special cells or tissue located inside the testes that secrete testosterone; also called interstitial cells.

Libido--(Latin) Sexual drive. Lice--Small, nonflying, biting or sucking insects that are true parasites of humans, animals, and birds. Biting lice belong to the order Mallophaga; the sucking or true lice belong to the order Anoplura.

Lick Tank--A tank containing a liquid feed supplement for cattle. The cattle obtain the feed by licking a wheel or ball that rotates in the liquid. As the wheel or ball turns, the liquid adheres to it and is brought to the surface.

Licks--A United States term given to boggy grounds with salt springs, where cattle go to lick the salt.

Life Cycle--Life history; the changes in the form of life that an organism goes through.

Life History--Habits and changes undergone by an organism from the egg stage to its death as an adult.

Lift--(1) A joint of meat, especially beef, from the thigh. (2) Elevating or pulling power of a pump. (3) To loosen and remove seedlings or transplants from the seedbed or transplant bed prior to transplanting. (4) A hay fork. (5) A fork for lifting heavy loads.

Ligament--Any tough, dense, fibrous band that connects bones or supports viscera.

Ligase--An enzyme that splices segments of DNA together.

Light--(1) The form of radiant energy consisting of wavelengths lying within the limits perceptible by the normal human eye, and, by extension, the shorter and longer wavelengths, the ultraviolet and the infrared light, invisible to the eye but which may be recorded photographically.

Light can be absorbed by various substances and transformed into heat. Its excess may produce fading, the destruction of green color in plants, but an insufficiency can also cause lack of chlorophyll production. The coloration of fruits is dependent upon sufficiency of light. The growing parts of plants respond to the stimulus of the direction from which the light comes. See Photosynthesis, Phototropism. (2) To become ignited; to take fire. (3) Designating a deficiency or lack in degree, such as a light rain or a light crop. (4) When applied to food or drink it can have several definitions. It could mean reduced calories, fluffy (full of air), pale, low in sodium, mild in flavor, and/or less alcohol.

Light Bay--A horse color; light tan with a black mane and tail.

Light breed--A smaller and more refined type of a particular kind of livestock, as the Thoroughbred horse, the Leghorn chicken, etc.

Light Chestnut--A horse color; light, yellow-gold.

Light Dun--A horse color; a dun imposed on a sandy bay or sorrel.

Light Feeder--(1) An animal that is being fed for maintenance and normal growth but not for quick finish or fattening. (2) An animal that does not eat as much as most animals of its class.

Light Grazing--Allowing livestock to partially graze an area, such as a pasture or range.

Light Horse--A horse that weighs between 900 and 1,400 pounds at maturity.

Light Meter--A device used to measure light intensity; the measurement is usually in foot candles.

Light Ration--(1) A limited or scanty ration in contrast to a liberal ration. (2) A ration that is loose and bulky in relation to its weight.

Light-handed--Denoting a rider who handles a horse well with a minimum of tugging or jerking on the bridle.

Light-Harness Horse--An American horse produced for speed and performance such as Standard and American Trotter.

Lightning Arrester--A device used across the circuit of a piece of electrical equipment to protect it or its operator from abnormal surges of high voltage, such as from lightning.

Ligule--A strap-shaped organ or body: (a) particularly, a strap-shaped corolla, as in the ray flowers of the Compositae; (b) also, a projection from the top of the sheath in the Gramineae, Palmae, and some other plant families.

Like Produces Like--A rule of thumb in breeding; the offspring will bear a close resemblance to the parents.

Limb--(1) A lateral branch of a tree or shrub. (2) The leg or wing of an animal. (3) To cut off a limb of a tree.

Limberneck--A disease of fowls resulting from ingestion of food contaminated with Clostridium botulinum, characterized by flaccid paralysis of the body. This is the same species of microorganism that causes botulism poisoning, usually from improperly canned meats and vegetables. The toxic chemical is known as botulin or botulismotoxin.

Limburger--A soft cheese within a strong flavor and odor. Limited Feeding--(1) The feeding of livestock to maintain weight and growth but not to fatten or increase production. (2) Restricting an animal to less than maximum weight increase.

Limosis--Intense hunger.

Limousin--A breed of beef cattle that originated in southern France. They are golden-red and are recognized for their high-yielding carcasses. Lincoln--A long-wooled breed of sheep from Lincolnshire, England. A large, white-faced mutton breed, it is popular in New Zealand. The mature ewes weigh up to 250 pounds.

Line--(1) The reins of a harness. (2) A rope, cable, string, wire, tube, etc., for tying or hanging objects, or conducting electricity, water, gas, etc., as a power line, gas line, or milk line. (3) A boundary or limit, as a fence line, property line. (4) In marketing, the whole of a herd of sheep. (5) A group of plants or animals that retain their uniform appearance in succeeding generations.

Line Breeding--Mating of selected members of successive generations among themselves in an effort to maintain or fix desirable characteristics.

Line Test--(1) A test in which a series of samples are taken from the milk supply of the whole herd during milking or milk processing; used in the bacteriological control examination of the milk supply. (2) The rapid agglutinin test used to detect abortion infection in herd milk. (3) A test used for the determination of the vitamin D content of milk. (4) A test to determine the degree of calcification of a growing bone; a measure for rickets.

Liniment--A preparation used for bathing or rubbing sprains, bruises, etc., usually containing a counterirritant.

Linkage--The association of characters from one generation to the next due to the fact that the genes controlling the characters are located on the same chromosome linkage group. The genes located on a single chromosome or the characters controlled by such genes. Linnaean--Conforming the principles of binomial nomenclature of all plants and animals, into genus and species, as advocated by Carl von

Linne, a Swedish botanist (1707-1778), who Latinized his name to Carlus


Linseed Cubes--A livestock feedstuff, consisting of a mixture of linseed oil meal with flaxseed by-products, or both. Linseed Meal--The product resulting from grinding linseed oil cake produced when flaxseed is pressed to recover linseed oil. Only batches unfit for feed are used as a fertilizer by organic gardeners.

Lip--(1) In a dam, a small wall on the downstream end of the apron to break the flow from the apron. (2) One of the edges of a wound. (3) Either of the two external fleshy folds of the mouth opening. (4) Either one of the inner or outer fleshy folds of the vulva.

Lip and Leg Ulceration--A viral disease of sheep, characterized by lesions on the lips, face, lower portion of the legs, and between the toes. Also called ulcerative dermatosis of sheep.

Lip Strap--The small strap running through the curb chain from one side of the bit shank to the other. Its primary function is to keep the horse from taking the shank or the bit in its teeth.

Lipase--A fat-digesting enzyme.

Lipis--A group of organic substances that are insoluble in water but soluble in such materials as acetone, chloroform, ether, and xylene; e.g., fats, waxes, and steroids including cholesterol.

Lipoid--Concerning fat or fatty tissue.

Lipolysis--The hydrolysis of fats by enzymes, acids, alkalis, or other means, to yield glycerol and fatty acids.

Liquid Manure--The liquid excrement from animals, mainly urine, collected from the gutters of barns into large tanks and hauled to the fields.

Liquid Smoke--A liquid mixture applied to meats in curing, especially to ham and bacon, to replace curing by wood smoke.

Listeriosis--A sporadic, specific bacterial disease of ruminants primarily involving the central nervous system (brain and spinal cord). On occasions it may result in abortions in sheep and cattle. It is caused by Listeria monocytogenes, also infective for nonruminant mammals (including people) and chickens. Also called listerelosis, circling disease.

Listless--Lethargic, lifeless, lacking energy. A listless animal would lie around and appear weak and not be aroused by the stimuli that usually arouse it.

Litter--(1) On a forest floor, the uppermost surface layer of debris, leaves, twigs, and other organic matter, undecomposed or slightly altered. In a technical description of a soil profile, it is generally designated by the letter O. (2) Accumulation of leaves, fruits, twigs, branches, and other plant parts on the surface of the soil. See Mulch. (3) A group of young animals born at a single birth, as a litter of pigs, etc. (4) See Bedding.

Litter Floor--The floor of a poultry house that is composed of straw and shavings or ground corncobs, droppings, and other waste materials, and builds up during one laying year.

Little-pig Anemia--See Anemia in Suckling Pigs.

Livability--The inherited stamina, strength, and ability to live and grow; important character of all young animals, such as baby chicks, lambs, pigs, etc.

Live Delivery--A common guarantee by hatcheries, of delivering live chicks by the addition of two or more chicks per order of one hundred.

Live Foal Guarantee--A common guarantee by stallion owners that a live foal will result from the breeding service. In case of failure, the breeding fee is not charged or, if already charged, is refunded.

Live Virus--A virus whose ability to infect has not been altered.

Live Weight--The gross weight of a live animal as compared with the dressed weight after slaughter.

Liver--A glandular organ in people and other animals that secretes bile and performs certain metabolic functions. Liver of various animals and fowls is edible, and its extracts are used medicinally, especially for anemia.

Liver Chestnut--A horse color; a dark shade of chestnut.

Liver Fluke--Fasciola hepatica, and Fascioloides magna; a macroscopic parasite of sheep, cattle, and swine that lodges in the liver, causing liver rot.

Liverpool Bit--A curb bit used for controlling heavy harness horses. See Curb Bit.

Livestock--Farm animals raised to produce milk, meat, work, and wool; includes beef and dairy cattle, swine, sheep, horses, and goats; may also include poultry.

Livetin--A water-soluble protein found in egg yolk.

Llama--(1) Auchenia llama; a ruminant quadruped of South America, allied to the camel, but humpless, smaller (about 3 feet high at the shoulder) and with a long, wooly coat; used in the Andes as a beast of burden. (2) Llama's wool or material made from it.

Loading Chute--An inclined chute that is used for animals to walk from the ground into a truck or trailer.

Loafing Barn--A light type of building usually attached to the main dairy barn or milking parlor where cows may be turned loose after milking for exercise and comfort. Hay and silage are usually supplied in side racks or bunkers.

Lobe--Any segment of an organ, especially if rounded.

Local Effect--An effect that a toxic substance causes at its original contact point with the body, e.g., eye damage.

Lock--(1) A small tuft of cotton, wool, flax, etc., fibers. (2) Small bits of wool that are packed separately for market (Australia). (3) A locule or the cotton in a locule. (4) The single cavity in an ovary.

Locker Beef--Beef that is raised primarily for sale to individuals for home consumption. It is usually bought at the farm.


Loco--(Spanish, insane) (1) The name of various poisonous plants in arid regions of the genera Astragalus, Hosackia, Sophora, and Oxytropis; all of the family Leguminosae. Because they contain excessive selenium they are toxic to horses, cattle, and sheep. (2)

Locoism. Poisoning with loco. Also known as loco disease, and loco poisoning. See Earl Loco, Rocky Mountain Crazyweed.

Locus--The position on or region of a chromosome where a gene is located.

Lofty--Designating wool or a woolen fabric that has springiness when compressed, is bulky in comparison with its weight, is light in condition, and has an even, distinct crimp.

Log--(1) An unhewn, sawed or cut length of a trunk or large limb of a tree. See Saw Log. (2) In the preparation of chip steaks, the molded, frozen piece of meat from which the steaks are cut. (3) To fell trees for lumber.

Loggering--A riding posture in which the rider holds the horn of the saddle rather than sitting free and erect in the saddle.

Loin--(1) The part of the body of animals on each side of the backbone that lies between the floating ribs and hipbone. (2) A wholesale or retail cut of meat that comes from the loin of a carcass. See Short Loin, Tenderloin.

Loin Chop--A retail cut of meat taken form the loin section of the carcass of a lamb, veal, or hog.

Loin Disease of Cattle--Botulism of cattle that results from eating bones or putrid flesh containing toxins produced by the organism Clostridium botulinum. (Cattle eat bones or putrid flesh because of a depraved appetite usually resulting form a phosphorus deficiency.) Symptoms of botulism are weakness in the hindquarters and loss of muscle control.

Loin Eye (Rib Eye)--(1) Area of loin eye or rib eye at the twelfth rib; used in carcass evaluation to determine the yield grade of carcass. (2) Cross section of the large muscles that lay on either side of the backbone in the loin area of a carcass.

Lone Star Tick--Amblyomma americanum, family Ixodidae; a bloodsucking tick that infests cattle, people, horses, dogs, goats, hogs, and many wild mammals.

Long--(1) Designating a person who has brought more contracts than he has sold. Long hedges are purchases of futures made as a hedge against the sale of the cash commodity (short). (2) Designating a pulse beat that is longer than normal.

Long Feed--(1) Any coarse, unchopped feed for livestock, such as fodder, hay, straw. (2) Feeding for a long period of time as contrasted with a short feed period.

Long Horse--A horse that can travel far and fast (western United States).

Long Wool--Wool from such English breeds as the Lincoln, Leicester, and Cotswold. The wool is large in diameter and up to 12 or 15 inches in length.

Long Yearling--(1) An animal more than a year old. (2) A senior yearling of livestock-show class.

Long-coupled--Too much space between the last rib and the point of the hip of an animal.

Long-nose Cattle Louse--Linognathus vituli, family Lingonathidae; a bloodsucking insect that infests cattle.

Long-tailed Sheep--An undocked sheep. common in the United States and Europe.

Long-wool Breeds of Sheep--The principal breeds of long-wool, mutton-type sheep in the United States; Lincoln, Cotswold, Romney Marsh, Black-Faced Highland, and Leicester.

Longeing--Training a horse at the end of a 25- to 30-foot (7.6 to 9 meters) line.

Longevity--Length of life; a long duration of life.

Longhorn Cattle--(1) Cattle of the Spanish type first brought into Mexico in 1521; much of the early cattle of the western range, United States, were derived from this type. (2) A breed of cattle in England probably of Spanish derivation. (3) See Texas Longhorn.

Longwool Crossbreed--A sheep crossbred from two different breeds, one being a long-wool type. A common sheep in western sheep ranches in the United States.

Loose Hay--Hay stored in the hay mow or stack without chopping, baling, or compressing.

Loose Housing--A management system for cattle wherein the adult animals are given unrestricted access to a feeding area, water, a resting area, and an adjoining open lot. In dairies, the lactating animals pass through a milking room at milking time. Other dairy animals may be in separate pens, lots, or buildings.

Loose Rein--A condition in riding or driving in which the reins on the harness of a horse are generally relaxed.

Loose Side--The left side of a beef carcass. See Tight Side.

Lope--In a horse, a slow gallop.

Lordosis--In veterinary medical vernacular, a mating posture assumed by many females in which they lower the forebody toward the ground and slightly elevate the hind end, straightening the arch of the back and tipping the pelvis slightly forward.

Loss of Cud--An old, false idea that a cow sometimes would lose her cud and would have to be supplied with another, such as placing a rag or other material in the mouth. Failure to regurgitate and chew cud is an indication of illness. See Cud.

Lot--(1) A small piece of enclosed land usually adjacent to a barn or shed in which horses, mules, cows, etc., are allowed to exercise. (2) Any particular grouping of animals, plants, seeds, fertilizers, etc., without particular regard to number, as a seed lot. (3) A small tract of land, usually less than an acre, on which a house is constructed.

Louse--A small wingless insect that usually lives as a parasite on humans or domestic animals.

Low Intensity Animal Production--Systems of producing animals that strive to use less capital, energy, and fewer purchased inputs than conventional confinement systems; e.g., a pasture and hutch system for swine production.

Low Wool--Wools of low quarter-blood or lower in quality.

Lugger--A horse that pulls at the bit.

Lumbar--The region of the back between the thorax and the pelvis; refers to the loins.

Lumen--The space in the interior of a tubular structure such as an artery or the intestine.

Lumpy Jaw--See Ray Fungus.

Lumpy Skin Disease--An acute viral disease of cattle, characterized by the eruption of variably sized cutaneous nodules, edema of one or more limbs, and swelling of the superficial lymphatic glands.

Lung Fever--See Hemorrhagic Septicemia.

Lunker--(1) A very big, awkward, heavy-boned horse. (2) Any animal that is considerably larger than the average.

Luster--(1) The property of wood, independent of color, which causes it to reflect light and to exhibit a sheen. (2) The natural gloss or sheen characteristic of the fleeces of long-wool breeds of sheep and Angora goats.

Lutein--A hormone, prepared from the dried corpus luteum of the sow; used to cause ovulation. See Corpus Luteum, Follicle-stimulating Hormone.

Luteinizing Hormone--In animals, a hormone of the anterior pituitary gland that stimulates ovulation and development of the corpus luteum in females and secretion of testosterone by the interstitial cells in males. See Corpus Luteum, Follicle-stimulating Hormone.

Lymph--A nearly colorless fluid made up of the liquid portion of the blood and the white corpuscles but free from the red corpuscles. It is derived from the blood by seeping through the walls of the capillaries (very minute blood vessels) which join the bloodstream in the vicinity of the heart.

Lymphatic--Referring to the system of vessels returning lymph from the tissues to the bloodstream.

Lymphocyte--A kind of white blood cell produced by lymph nodes and certain other tissues, and associated with the production of antibodies.

Lymphoid--Referring to lymph.

Lympholeukosis--See Lymphomatosis.

Lymphoma--A cancer of cells of the immune system (e.g., lymphocytes), where the tumor is confined to lymph glands and related tissues, such as the spleen.

Lymphomatosis--A disease of fowls caused by the formation of tumors of lymphoid tissue in different parts of the body; a form of avian leukosis complex.

Lysin--Antibody that dissolves or disintegrates cells: bacteriolysin dissolves bacteria, hemolysin dissolves red blood cells.

Lysis--(1) The gradual disappearance of the symptoms of a disease. (2) The destruction or dissolving of cells.

Lysozyme--An enzyme present in certain body secretions that can destroy certain kinds of bacteria.


Macro--Prefix meaning large, long; visibly large.

Macronutrients--Includes primary plant nutrients N, P, and K; and secondary plant nutrients Ca, Mg, and S. See Micronutrient.

Macroorganisms--Plant, animal, or fungal organisms visible to the unaided eye.

Macroparasite--Parasite visible to the naked eye.

Macroscopic--Visible to the human eye without the aid of a microscope.

Mad Itch--(of cattle) See Aujeszky's Disease.

Mad Stone--See Hair Ball.

Madness--See Rabies.

Maggot--A vermiform larva; a larva without legs and without well-developed head capsule; the larva of a fly.

Magnum--The part of the oviduct of a bird located between the infundibulum and the isthmus; the source of the albumin of an egg.

Maiden--(1) A year old, single-stemmed seedling fruit tree used for budding or grafting. See Whip. (2) An unbred female animal.

Maiden Flight--The flight taken by a queen bee during which mating occurs.

Mailing Cage--A shipping container for a queen bee.

Maine Anjou--A breed of large beef cattle originating in France. The animals are horned and vary in color from red with white markings to dark roan.

Maintenance Ration--The amount of feed needed to support an animal when it is doing no work, yielding no product, and gaining no weight.

Malanders--In horses, an eczema on the posterior portion of the foreleg knee. Pustules also appear on the neck.

Malarial Fever--See Equine Infectious Anemia.

Malathion--An organic, phosphorus insecticide. Technical grade malathion (95 to 98 percent pure) is a viscous, dark brown liquid with a strong, offensive odor somewhat like that of garlic. Widely used to control pests, it is the least toxic of phosphorus insecticides.

Malde Caderous--An infectious horse disease caused by Trypanosoma equinum, family Trypanosomatidae; a protozoan parasite that infests the blood plasma. It is characterized by rapid loss of flesh, red urine, anemia, partial paralysis, and edema. Endemic in South America.

Male--(1) Designating an animal capable of producing spermatozoa, or male sex cells. (2) Designating the stamens of a flower. (3) Designating a staminate plant.

Male Process--Genital eminence.

Malformation--Any unusual, abnormal growth, organ, or part of a plant or animal.

Malignant--Tending to grow worse; exceedingly noxious, dangerous, infectious, or that condition which terminates in death, as a malignant growth.

Malignant Catarrhal Fever--Also known as snotsiekte, an acute generalized disease of cattle and buffaloes characterized by high fever, profuse nasal discharge, severe hyperemia, diffuse necrosis of oral and nasal mucosae, leukopenia, opthalmia, corneal capacity and enlargement of lymph nodes. Four syndromes are recognized: the peracute, intestinal, head and eye, and mild. The natural disease is usually of the head and eye form with low morbidity and high case fatality rates.

Malignant Edema--An acute, fatal wound infection disease caused by Clostridium septicum, family Bacillaceae, which affects horses, cattle, sheep, swine, and people. Characterized by swelling and gangrene.

Malignant Pustule--Localized skin lesion of anthrax in people.

Malignant Tumor--A tumor with the potential for invading neighboring tissue and/or metastasizing to distant body sites, or one that has already done so.

Mallein--A diagnostic agent processed as an extract from Malleomyces mallei (glanders bacillus); used principally in the diagnosis of glanders in horses. See Glanders.

Malnutrition--An unhealthy condition resulting from either poor feed or lack of feed.

Malocclusion--A deviation of the proper closing or meeting of the upper and lower teeth.

Malt--A grain product, rich in protein and carbohydrates, made by allowing the grain to sprout for a sufficient length of time to produce adequate amounts of enzymes and then dried. The term malt, unqualified, implies barley malt.

Malt Cleanings--A livestock feedstuff obtained from the cleaning of malted barley or from the recleaning of malt that does not meet the minimum protein standard of malt sprouts.

Malt Sprouts--A livestock feedstuff obtained by the removal of the sprouts from malted barley together with the malt hulls, and other parts of malt and foreign material unavoidably present. It should contain not less than 24 percent of protein. The term malt sprouts when applied to a corresponding portion of other malted cereals shall be used in qualified form: e.g., "Rye Malt Sprouts," "Wheat Malt Sprouts," etc.

Maltase--An enzyme that splits maltose into two molecules of glucose.

Maltese--A breed of asses, probably of Arabian origin, first imported into the United States from the Island of Malta at the end of the eighteenth century.

Mammary Gland--Udder or breast. In female mammals, a milk-secreting gland for the nourishment of the young. It is rudimentary in male mammals.

Mammary System--The udder, blood vessels, and teats of an animal, especially of the dairy cow.

Mammary Vein--Any of the numerous, long, tortuous, prominent, large veins or blood vessels found just under the skin along the belly to the udder of a dairy cow.

Mammitis--See Mastitis.

Mammoth Jack--A distinct breed of ass developed in the United States in which the Catalonian ass was an important influence. The Mammoth Jack is larger and heavier boned than other breeds of ass and for this reason is better suited for use in mule breeding. Also called American Jack.

Man-Killer--A vicious horse that will attack its handlers.

Management of Pastures--The handling of animals and plants in such a manner that the stand of desirable forage is not depleted and at the same time provides a sufficient supply of palatable, nutritious forage for the producing or growing animal for as long a time as is possible during the grazing period.

Mandible--The bone of the lower jaw; the lower jaw.

Mane--Long, heavy hair that grows about and on the upper side of the neck of the horse and some other animals.

Mange--A group of contagious skin diseases in livestock caused by certain sarcoptic parasitic mites.

Mange Mite--See Scab Mite.

Manger--A trough or other receptacle of metal, wood, concrete, or stone, in which fodder is placed for cattle to eat.

Manure--(1) Excreta of animals, dung and urine (usually with some bedding), used to fertilize land. (2) In Europe, any material that contains the essential elements of plant nutrients, as chemical fertilizers, excreta of animals, etc. See Compost.

Manure Pit--A storage unit in which accumulations of manure are collected before subsequent handling or treatment, or both, and ultimate disposal. Water may be added in the pit to promote liquefaction so the manure can be spread on fields through a sprinkler irrigation system.

Manure Salts--Crude salts in natural deposits, containing a high percentage of potash (K2O) in the form of the chloride. Sometimes used as fertilizer.

Manure Spreader--A wagon-type implement for carrying barnyard manure to the field, shredding it and spreading it uniformly on the land. The power for the spreading mechanism and conveyor is supplied from the rear wheels or from a tractor power take-off.

Marbled--Mottled or streaked, like certain kinds of marble. Used to describe the intermuscular fat in meat.

Marbling--The desired distribution of the fat in the muscular tissue of a cut of meat that gives it a spotted appearance. The degree of marbling is used in the grading of beef carcasses.

Marchigiana--A breed of large beef cattle that originated in Italy. They are horned and gray.

Mare--(1) A mature female horse. (2) The insoluble residue left after processing fruits, sugarcane, and sugar beets.

Mare Mule--A female mule. See Mule.

Mariculture--The growing of marine animals such as fish and shrimp under controlled conditions in saltwater rather than in freshwater. See Aquaculture.

Market Barrow--A castrated male hog finished or fattened for meat purposes.

Market Bird--Any fowl produced and fattened for meat purposes.

Market Classes and Grades--Various market classes and grades established by the United States Department of Agriculture to sort livestock according to conformation, finish, quality, use, age, sex, and weight.

Market Grade--A set of descriptive terms, such as prime, choice, etc., used in livestock marketing to designate the comparative value of animals based on differences in type, conformation, degree of finish, etc.

Market Grades of Cows and Bulls--Determined by the age and fatness of the animal. The grades are: commercial, utility, cutter, canner.

Market Grades of Lambs--Prime, choice, utility, canner, cutter, cull.

Market Grades of Slaughter Steers and Heifers--Market grades of beef animals that are to be slaughtered are determined by the age of and the amount of fat on the animal that is indicative of the amount of marbling in the meat. The grades are: prime, choice, select, standard. Cattle are also graded by the percentage of lean retail cuts of meat the animal is expected to yield. See Marbling, Maturity, Yield Grade.

Market Grades of Swine--Various market classes of swine established by the United States Department of Agriculture: United States Number 1, United States Number 2, United States Number 3, and cull.

Marking--(1) Castrating, docking, branding, and ear marking. (2) Selection and indication, usually by blaze or paint spot, of trees that are to be cut or retained in a cutting operation.

Marking Harness--A harness strapped to a ram that marks a ewe's rump when she is bred by the ram.

Marrow--(1) A soft, yellow or red, fatty tissue that fills the cavities of most bones. (2) The pith of plants.

Marrowfat--Any of the several varieties of cultivated, large-seeded peas.

Martin Heifer--See Freemartin.

Martingale--A leather strap attached to the girth of a horse's saddle or harness on one end, with the other divided and passing between the front legs and tied to the noseband of the bridle. It stops the horse from rearing.

Masculine Head--In cattle, the brightness of eye, strong muzzle, horn character, and neck attachment that shows the vigor, alertness, and strength associated with a male.

Masculine Sex Character--In male animals, vigor, body build, altertness, and aggressiveness; desirable characteristics in animals such as bulls and stallions.

Masculine Style--In stock judging, the desirable characteristics of a male animal: i.e., up-headed, straight through the muzzle, wide between the ears, bold and clear in the eyes, wide in body conformation, and vigorous in appearance.

Mash--(1) A mixture of grain and other ingredients with water to prepare wort for brewing operations. (2) A ground feed of cereals and malt, etc., fed in a wet or dry form to livestock and poultry. Also called crowdy. See Wort.

Mash Concentrate--A poultry mash containing 20 to 40 percent protein.

Masked--Designating disease symptoms that are hidden.

Mass Selection--(1) In plant breeding, the selection of a large number of plants for propagation from which the off-type, low-yielding, inferior, and disease-susceptible plants have been eliminated. (2) In animal breeding, the selection for breeding purposes of animals on the basis of their individual performances, type, or conformation.

Massive--(1) Indicating a large-sized and deeply muscled animal; designates an ideal quality in a draft horse. (2) (Soil structure) Large uniform masses of cohesive soil that sometimes have irregular cleavage, as in the C horizons of many fine-textured clay soils. See Soil Structure.

Masticate--To chew; to prepare food for swallowing and digestion.

Mastitis--An infectious or noninfectious inflammation of the udder. All domestic female animals are susceptible, but it is most common among cows, ewes, and goats. It causes serious economic loss. Symptoms include decreased production, varying degrees of abnormal milk, heat, pain, and swelling of the udder, followed by a permanent firmness (fibrosis) of affected parts. Also called garget, felon quarter, weed, bad quarter, mammitis.

Mate--(1) To pair off two animals of opposite sexes for reproduction.

Mating may be for a single season or for life. (2) In plants, to be cross pollinated.

Maternal Breeding Value--A prediction of how the daughters of a bull will milk based on weaning weight information. The accuracy figure is the amount of reliability that can be placed on the breeding value.

Maternal Calving Ease of First Calf--Calving ease ratings of daughters of bulls, when they give birth, as reported to breed associations by producers, values above 100 are superior.

Maternal Inheritance--Inheritance from mother to offspring unaffected by inheritance from the father.

Maternal Instinct--The natural instinct of all female mammals to nurse and protect their young.

Maternal Milk--A measure of the amount of calf weight that results form the milk production of a sire's daughters.

Maternal Weaning Weight--Measure of a sire's ability to transmit

maternal performance, expressed in weaning weight of his daughters'

calves. It is a combination of milk production and growth rate that a sire transmits through his daughters.

Maternity Pen--A special pen in a barn where animals about to bring forth their young may be isolated from the rest of the herd.

Mating Season--The season of the year when animals naturally breed and when conception is normally high. It varies with different species.

Matroclinous--Resembling the female parent. See Patroclinous.

Matron--A mare that has produced a foal.

Matter--(1) Purulent discharge; pus. (2) To discharge matter; to generate pus.

Maturation--(1) Becoming mature or ripe. (2) Changes in cell division, especially in reproductive elements, in which the number of chromosomes in the nucleus of the new cells is half that of the original.

Mature Class--In the show ring, dairy cows five years of age or older that are in milk.

Mature Equivalent Factor--An age conversion formula used to predict the expected mature milk record for a cow, based on a previous year's milk production. It is frequently used in cattle selection and breeding.

Maturity--(1) A state of full or complete growth development or ripeness. (2) The ability of a plant or plant part to withstand the cold. (3) Animals old enough to reproduce. (4) A designation of the age of a beef animal at the time of slaughter. "A" maturity indicates an age range of nine to thirty-six months; "B" maturity indicates thirty to forty-two months; "C" indicates forty-two to seventy months; "D" maturity indicates seventy-two to ninety-six months, and "E" maturity indicates more than ninety-six months. The maturity classification is based on evidence in the carcass such as bone ossification. Maturity combined with marbling gives the basis for carcass quality grade. See Marbling; Quality Grade.

Maverick--(1) Any unbranded animal, particularly a calf. Named after Samuel A. Maverick, a lawyer and a nonconformist Texan (18031870) who refused to brand his cattle. (2) A motherless calf (western United States).

Maxilla--The jawbone, particularly the upper one in vertebrates. In insects and arthropods, the two accessory jaws or appendages immediately behind the mandibles.

Mealy Gray--The rusty blue color of a horse's coat.

Measles in Beef--The presence of one or more cyst stages, in the muscles of a beef carcass, of Taenia saginata, a parasite of people. Under United States Federal Meat Inspection regulations, carcasses extensively infested with these cysts are condemned.

Measles in Pork--The presence of one or more cyst states, in the muscles of a hog carcass, of Taenia solium, a parasite of people. Under Federal Meat Inspection regulations, carcasses extensively infested with these cysts are condemned.

Meat--(1) The edible flesh of an animal. (2) The kernel of a grain or nut. (3) The entire egg except the shell.

Meat Animal--Any animal produced primarily for its meat-producing characteristics, whether for breeding or slaughter.

Meat Bird--A fowl produced primarily for its meat, in contrast to a fowl kept especially as an egg producer. See Broiler.

Meat Curing--Any of several methods of processing meats and meat products so they will keep in usable condition for a satisfactory period of time: salting, pickling, smoking, etc., are the common methods.

Meat Inspector--A graduate veterinarian, engaged by regulatory authorities to inspect all meats as they pass through the slaughterhouse or packing plant, to certify that they are wholesome food products.

Meat Meal--A livestock feedstuff supplement which is the ground, dried, rendered residue from animal tissues exclusive of hoofs, horns, blood, manure, and stomach contents except in such traces as might occur unavoidably in good factory practice. Also called dry-rendered tankage.

Meat-and-Bone Scrap--A livestock feedstuff that is the product obtained by the dry rendering of the meat and bone substance of slaughtered animals in the meat packing industry.

Meat-type Hog--An antiquated term denoting a well-muscled hog that has good length of body and an above average percentage of ham, loin, and shoulder.

Meaty--(1) Designating a well-fleshed animal. (2) Designating a characteristic of good cheese snowing flexibility. It will tear but not break short and is not dry or brittle (3) Any cut of meat that shows a high percentage of good muscle structure. (4) Designating spareribs cut with a heavy layer of the bacon left on.

Mecate--A special kind of riding horse reins often made of horse hair (western United States).

Mechanical Buffer--A machine used in the final operation of plucking feathers from poultry slaughtered for market. Also called buffer.

Mechanical Mainpulation--Collecting semen for artificial breeding purposes by massaging the male's genital organs or by other use of the hand to produce ejaculation.

Mechanical Poultry Picking--The removal of feathers in dressing poultry for the market by the use of machines in contrast to removal by hand labor. See Mechanical Buffer.

Meconium--(1) The first excreta of a newborn animal. (2) The juice of the opium poppy, Papaver somniferum.

Media--(1) The middle coat of an artery. (2) The plural of medium. (3) Material for artificial propagation of various microorganisms. (4) Any means through which communication of any type is accomplished. (5) Soil or soil-like material in which plants are grown.

Median Lethal Dose--([LD.sub.50]) The amount of concentration of a toxic substance that will result in the death of 50 percent of a group of test (target) organisms upon exposure (by ingestion, application, injection or in their surrounding environment) for a specified period of time. (Complementary to median tolerance limit, ([TL.sub.50].) Median Plane--A plane that runs from the anterior to posterior ends of an animal that separates it into two equal parts.

Median Tolerance Limit--[TL.sub.50] The concentration of some toxic substance at which just 50 percent of the test (target) animals are able to survive for a specified period of exposures. (Complementary to Median Lethal Dose, [LD.sub.50].)

Medication--(1) The application of medicines, salves, etc., to an injured or sick animal. (2) The forced introduction of a chemical, usually a water-soluble salt in solution, into the sapstream of a living tree to kill it or make it repellent to insect attack, or into a freshly felled tree to destroy barkbeetle and woodbeetle broods.

Mediterranean Fever--See Undulant Fever.

Medium--(1) Any of a number of natural or artificial substances, pastelike or liquid, in or on which microorganisms, such as bacteria and fungi, can be cultured. (2) A soil or material, such as sand, peat moss, vermiculite, etc., in which plants are raised or cuttings are rooted, especially in the greenhouse. (3) A market grade of roses that has stems 12 to 8 inches in length. (4) One of the six recognized grades of meat, lying between good and common.

Medium Eggs--A United States size grade of eggs, between small and large, which specifies a minimum net weight of 21 ounces per dozen with no individual egg under the rate of 20 ounces per dozen.

Medium Wool Sheep--Any of several breeds of sheep intermediate between the fine wool and long wool breeds, desirable for meat as well as wool; e.g., Cheviot, Columbia, Corriedale, Dorset, Hampshire, Oxford, Panama, Shropshire, Southdown, Suffolk, Tunis.

Medium Wools--Usually refers to one-half blood, three-eighths blood, and one-quarter blood wools, or wools grading 50s to 62s.

Medium-spectrum Antibiotic--An antibiotic that attacks a limited number of gram-positive and gram-negative bacteria.

Medulla--The inner layer or part of an organ.

Mega--(1) A prefix meaning one million. (2) A prefix meaning large or in large numbers.

Megaspore--A spore that has the property of giving rise to a gametophyte (embryo sac) bearing a female gamete. One of the four cells produced by two meiotic divisions of the megaspore-mother-cell (megasporocyte).

Megasporegametophyte--The few-celled haploid generation portion of a seed plant arising from a meiotic division and giving rise through meitosis to the female gametes. Female inflorescence.

Megspore-Mother-Cell--The cell that undergoes two meiotic divisions to produce four megaspores.

Meiosis--Cell division early in the reproductive process, and in the formation of sperm and ova in the testicles and ovaries. Each pair of chromosomes in the cell being divided separates, and one member of each pair goes to each of the two new cells formed.

Melanin--The black or dark brown pigment found in skin and hair cells.

Melanoma--Malignant melanoma is a cancer of the cells that produce the pigment melanin.

Melene--A white, waxy, crystalline hydrocarbon, extracted from certain types of paraffin, and from beeswax by dry distillation.

Melittology--That branch of entomological science concerned with bees.

Membrane--(1) A thin, flexible sheet of vegetable or animal tissue; the thin protoplasmic tissue connecting, covering, or lining a structure, such as a cell of a plant or animal. (2) The layer that surrounds fat globules of milk. Its nature is not definitely known: it may consist mainly of phospholipoids and a protein or proteins not completely identical with casein, albumin, or globulin. (3) A layer of low permeability material: e.g., bentonite (clay) soil, placed in the bottom of a farm pond to reduce seepage losses.

Menadione--Vitamin K3; an antihemorrhagic vitamin that is essential for all animals and people to control bleeding.

Mendel's Law (Medelian Law)--Gregor Johann Mendel (1822-1884), an Austrian monk, naturalist, and plant breeder, first demonstrated dominant and recessive genes in plant breeding, which also applies to some kinds of animal and people inheritance. For example: When a plant with the dominant gene for tallness (TT) is crossed with a plant with a recessive gene for shortness (ss), the first generation, [F.sub.1], will be distributed according to the following ratio. One plant, TT, homozygous (pure) true-breeding for tallness. Two plants, Ts, heterozygous for tallness and shortness. One plant, ss, homozygous (pure) true-breeding for shortness. When plants with Ts and Ts genes are crossed, the [F.sub.1] progeny will be in the same ratio, i.e., one TT, two Ts, and one ss.

Meningoencephalitis--An inflammation of the brain and its membranes. Merino--(1) A breed of small sheep that descended from Spanish stock believed to have originated in Africa. Wool from the Merino is of excellent quality, very fine, and about 4 inches in length. Raised chiefly in the United States and Australia for its fleece, it has been crossed with other breeds, especially in New Zealand, to make it a better mutton sheep. (2) A term used in the textile industries to denote wool from the Merino or very high quality wool.

Mesophiles--Parasites and often pathogenic bacteria that grow best at a body temperature of 98.6[degrees]F (37[degrees]C). Metabolic--Designating the chemical changes that take place in living plant and animal cells whereby one compound is converted to one or more other compounds.

Metabolizable Energy--The total amount of energy in feed less the losses in feces, combustible gases, and urine. Also called available energy.

Metabolized Milk--Milk produced by cows that have been fed irradiated yeast.

Metacercaria--The encysted larval stage of a trematode (fluke) that develops from another larval stage, the cercaria, and is infective to the final (definitive) host: e.g., the metacercaria of the common liver fluke of sheep and cattle encysts on blades of grass and is swallowed by sheep or cattle while grazing. See Flukes.

Metalimnion--(1)The layer of water between the epilimnion and the hypolimnion in which the temperature exhibits the greatest vertical rate of change, also more frequently termed the thermocline. (2) The zone in which temperature decreases rapidly with depth in a lake when it is thermally stratified in summer. See Epilimnion, Hypolimnion.

Metallic Flavor--An objectionable flavor in milk, butter, cheese, and ice cream, which results from metal contamination, particularly copper and iron.

Metamorphosis--A process by which an organism changes in form and structure in the course of its development, as many insects do. See Complete Metamorphosis.

Metaphase--That stage of cell division in which the chromosomes are arranged in an equatorial plate or plane. It precedes the anaphase stage.

Metaplasia--The abnormal transformation of an adult (mature), full differentiated tissue of one kind into differentiated tissue of another kind.

Metastasis--The spread of a malignancy to distant body sites by cancer cells transported in blood or lymph circulation.

Metestrus--The phase of the estrous cycle of nonprimates following estrus and characterized by the development of the corpus luteum and the preparation of the uterus for pregnancy.

Methane--C[H.sub.4]; an odorless, colorless, and asphyxiating gas that can explode under certain circumstances; can be produced by manures or solid waste undergoing anaerobic decomposition as in anaerobic lagoons and in silos. There are twelve species of bacteria capable of producing methane gas from manures and other biomes.

Methemoglobin--A rust-colored substance, formed when oxygen unites with an oxidized product of hemoglobin. The oxygen is not easily released form this combination, thus injuring the tissues. Its properties are in contrast to those of oxyhemoglobin, which is bright red and releases its oxygen readily. Methemoglobin results form blood decomposition or from poisoning of blood by nitrates, nitrites, and other substances.

Methionine--A sulfur-containing essential amino acid; indispensable for animals.

Methmoglobinemia--(1) A lack of oxygen in the blood due to oxidation of iron from the ferrous to the ferric state. (2) The presence of methemoglobin in the blood resulting in cyanosis. This can be induced by excessive nitrates, nitrites, and certain drugs, or to a defect on the enzyme NADH.

Methyl Formate--An insect fumigant.

Methyl Red--A chemical indicator; a dye stain used in determining the classification or taxonomy of certain bacteria such as Coliform bacilli.

Methylene Blue Reduction Test--A test for the bacteriological quality of milk that consists of placing methylene blue thiocyanate in the milk under controlled conditions. The more rapidly the methylene blue changes color, the greater the number of bacteria in the milk.

Metritis--Uterine inflammation.

Mett--A semidry, 100 percent pork sausage.

Mexican Blindness--An animal disease caused by a filarial parasite, Onchocerca volvulus, which is carried by blackflies, buffalo gnats, and turkey gnats. Also known as African river blindness.

Mexican Fruit Fly--Anastrepha ludens, family Tephritidae; a serious insect pest of citrus and other fruits in Mexico. At times it has appeared in the Rio Grande Valley of the United States.

Mexican Horse--A breed of horse directly descended from the Andalusian and Arabian breeds brought to Mexico more than 400 years ago by the Spanish conquerors.

Mexican Jack--The small, common burro, seldom used for breeding in the United States. Also called Spanish jack.

Micro--A prefix meaning one millionth (1/1,000,000) or very small.

Microbes--Minute plant or animal life. Some microbes may cause disease, while others are beneficial.

Microbial Insecticide--Microbes that are used to control insects. Of the millions of insects that have been identified, about 350 species have been classified as destructive pests. Like all living organisms, these pests are susceptible to diseases caused by bacteria, fungi, protozoa, and viruses. Research scientists have explored this avenue of control and have developed several strains of microbes that have potential to be effective in the control of insect pests. See Integrated Pest Management.

Microbiologist--A scientist concerned with the study of plant and animal microorganisms.

Microelements--Trace elements; micronutrients.

Micronutrient Elements, Essential--For plants: boron, chlorine, cobalt, copper, iron, manganese, molybdenum, and zinc. For people and animals: chlorine, copper, iron, manganese, molybdenum, zinc, sodium, iodine, selenium, vanadium, chromium, cobalt, nickel, fluorine, silicon, boron, and arsenic.

Microorganism--(1) An organism so small that it cannot be seen clearly without the use of a microscope; a microscopic or submicroscopic organism. (2) Any microscopic animal or plant that may cause a plant disease or have the beneficial effect of decomposing plant and animal residue that becomes humus.

Micropyle--The minute necklike opening in the integuments of an ovule, where the sperms enter.

Microspore--One of the four cells produced by the two meiotic divisions (mitoses) of the microspore-mother-cell (microsporocyte). It gives rise to a gametophyte bearing only male gametes. Also called pollen grain.

Middle Milk--The milk obtained from a cow during the middle of the milking period, as opposed to that obtained in the beginning and at the end. It has a higher fat content and a lower bacteriological count than the other two.

Middlings--(1) The coarse particles separated in the milling of wheat that contain the germ of the wheat grain and fine particles of bran. Higher in protein and digestible nutrients than bran, the middlings are used as a feed chiefly for hogs, calves, and poultry. Also called shorts. (2) The belly portion of a pork carcass from which bacon is cut.

Migratory Beekeeping--Movement of apiaries from one area to another to take advantage of honey flows from different crops and to pollinate the crops.

Mild--(1) Designating cheese that is not sharp or strong in flavor. (2) Designating a gentle animal.

Milk--(1) The natural, whitish or cream-colored liquid discharged by the mammary glands of mammals. Unless otherwise stated, milk usually means cow's milk. (2) The juices or fluids secreted by certain plants, as the milk of the coconut or the milk of immature kernels of corn. (3) To draw milk from the udder of a cow.

Milk Carton--A plastic or wax-coated, disposable, paper container used in retailing milk.

Milk Cistern--A part of a cow's udder; the cavity holding about one-half pint that is drained by the teat ducts.

Milk, Condensed--Milk that has had a large part of its water of constitution removed by evaporation. Sugar has been added as a preservative. See Milk, Evaporated.

Milk Derivative--Any product obtained from milk, such as butter and cheese.

Milk Dry--To draw out the last of the milk from a cow's udder; to strip.

Milk Dryer--Any mechanical device designed to remove most of the water from milk. The water may be evaporated from pans or from steam-heated rollers; or the milk may be sprayed into a stream of hot air. See Drier.

Milk Duct--The cavity in the teat that leads into the milk cistern. Also called teat cistern.

Milk Feed--In poultry husbandry, to feed chickens a fattening mash mixed with milk, six to ten days prior to marketing.

Milk Fermentation--The process by which a change is produced in milk as a result of the activity of one or more species of microorganisms.

Milk Fever--See Parturient Paresis.

Milk Flow--The amount of milk produced by a cow or by the entire herd in a day, week, season, etc.

Milk Goat--A goat bred primarily for milk production, as the Saanen and Toggenbrug. See Alpine, Iamancha, Nubian, Saanen, Toggenburg.

Milk Irradiator--A device that uses an electric arc or mercury vapor lamp to convert ergosterol in milk into vitamin D2.

Milk Ordinance--A law that sets forth regulations concerning the handling and quality standards of milk sold for public consumption.

Milk Record--A record of the amount of milk produced by a cow during a specified period. Used for evaluation in terms of money, profit, culling, or for registry.

Milk Replacer--A powder that when mixed with water is fed to young animals as the milk portion of their diet.

Milk Sample--A small amount of milk, normally collected at each farm each time the milk is collected; used for making certain tests at the dairy plant to determine butterfat content, bacterial count, etc.

Milk Sanitarian--A professional worker who specializes in the supervision of sanitary milk regulations.

Milk Sickness--(1) A disease of cattle caused by eating white snakeroot. Also called white snakeroot poisoning, trembles, milk sick. (2) A disease in people caused by ingestion of contaminated milk or milk from a cow affected by milk sickness.

Milk Stone--In dairy manufacture, a grayish-white, thin, chalky deposit that sometimes accumulates on heating surfaces, coolers, utensils, and freezers when improper washing methods have been used. It is largely a mixture of the minerals of milk and water.

Milk Substitute--In animal or dairy husbandry, any of a number of gruel feeds or mixtures fed to calves or pigs as a substitute for milk.

Milk Sugar--See Lactose.

Milk Teeth--The temporary teeth of a young animal that are much whiter and smaller than the permanent teeth.

Milk the Crop--To massage the crop of a slaughtered fowl so as to force feed remaining in its crop out of the mouth. It lessens the danger of spoilage of the dressed fowl.

Milk Vein--The subcutaneous, abdominal veins that are a continuation of the mammary veins of the udder of a cow. The largeness and tortuousness of the veins is used in judging dairy cattle.

Milk-borne Disease--Any human disease that results from the intake of pathogens in milk.

Milk-fat Basis--A method of paying for milk at receiving stations on the basis of price per pound of butterfat. See Butterfat.

Milk-fed--Designating animals fed largely on dairy products.

Milk-Feed Price Ratio--The pounds of dairy ration equal in value to one pound of milk, at prices existing at a particular time and place. The United States Department of Agriculture milk-feed price ratio is pounds of dairy concentrates, rather than the entire dairy ration.

Milk-souring Organisms--Groups of organisms, such as lactic streptococci and coliform bacteria, that are responsible for the souring of milk.

Milking--(1) The quantity or quality of milk removed from an animal's udder at one time. (2) The act of removing milk from an animal's mammary gland. (3) Pertaining to milking, as in milking machine.

Milking Machine--A mechanical device replacing hand labor in the milking of cows. The essential parts are teat cups, a vacuum pump, and a milker pail or milk line. Milk is drawn from the udder by application of alternate vacuum and atmospheric pressure.

Milking Parlor--In a dairy, an especially arranged and equipped room where cows are separately fed concentrates and milked by mechanical milking equipment.

Milking Shorthorn--A breed of dairy cattle that originated from the Shorthorn in England. Heavy milk producers, they are popular in Eng land and in the central United States. Predominant colors are red, white, or roan. Individuals weigh from 1,200 to 1,400 pounds.

Milkshed--A designated geographic area of milk production and consumption. Milky Disinfectant-See Coal-tar Creosote.

Milo Chop--A livestock feedstuff consisting of the entire grain of milo sorghum removed from the head and chopped or ground.

Milo Mill Feed-A livestock feedstuff that is a mixture of milo bran, milo germ, and a part of the starchy portion of the grain, produced in the manufacture of grits from milo grain.

Milt--(1) The roe or spawn of the male fish. (2) To impregnate with milt. (3) A ductless gland near the stomach and intestine of fowls. It contributes to the formation of new blood cells. See Spleen.

Milter--A male fish especially at spawning time.

Mineral--(1) A chemical compound or element of inorganic origin. (2) Designating the inorganic nature of a substance.

Mineral Elements--The inorganic components of soil, plants, or agricultural products.

Mineral Feeder--Any of a number of box or bin devices that automatically supplies a mineral or mineral ration in the feeding of livestock.

Mineral Mixture--Any feed containing salt, limestone, phosphates, minor elements, etc.

Mineral Wool--A substance outwardly resembling wool, presenting a mass of fine interlaced filaments, made by subjecting furnace slag or certain rocks while molten to a strong blast.

Mineralize--(1) To petrify. (2) To impregnate or supply with minerals. (3) To promote the formation of minerals. (4) The microbial breakdown of organic matter to release its minerals.

Mineralized Salt--A salt compound for animal feeding that is composed of a common salt base with the trace mineral elements, such as manganese, copper, iron, iodine, and zinc, added to it.

Miniature Broiler--A fast-growing broiler chicken, produced in six to eight weeks, about 11/2 pounds in live weight and about 1 pound in dressed weight. Usually marketed frozen and in individual packages, it is intended to be served whole and generally stuffed with dressing.

Mink Farming--The business of raising minks for their valuable fur. Mink are meat eaters and are often fed meat by-products.

Minnow--A small fish, often used for fish bait.

Minor Elements--See Micronutrient Elements, Essential.

Minorca--The largest breed of chickens of the Mediterranean class. They have long, strong bodies, enamel-white earlobes, and white skin. The eggshell is white. Varieties are Single-comb Black, Rose-comb Black, Single-comb White, Rose-comb White, and Single-comb Buff. Missouri Mule-A large mule from Missouri, United States, a state famous for mule production.

Missouri River-Bottom Disease--A disease of horses attributed to poisoning from eating arrow crotalaria, a legume found mostly in the southern United States.

Mites--Arachnids; very small spiders belonging to the order Acarina. These parasites constitute a very large group living in all parts of the world and are pests on both plants and animals.

Miticide--Any poisonous substance used to kill mites.

Mitosis--Cell division involving the formation of chromosomes, spindle fibers, and the division of chromosomes by a process of longitudinal splitting. Each of the resulting daughter cells thus has a full set of chromosomes as distinguished from reduction division or meiosis, in which the daughter cells have half the somatic number. See Meiosis.

Mix--(1) A formula; a combination of two or more ingredients, blended together for a specific purposes, such as feedstuff for livestock. (2) To cross or interbreed animals, plant varieties, etc., by chance.

Mixed Breeds--Farm animals that result from crossing different breeds of livestock.

Mixed Calves--A market class for a group of slaughter calves that are not uniform in grade.

Mixed Colored Eggs--Market eggs that are not uniform in color. Mixed Corn-All corn that does not meet the color rules for yellow corn or white corn.

Mixed Grain Sorghum--A market class that includes all grain sorghums not meeting the separate standards for white, yellow, red, and brown grain sorghums.

Mixed Hay-Hay that consists of two or more forage species, as a mixture of red clover and timothy.

Mixing Pens--In range management, a large pen in which a number of animals are confined. In handling goats, the does and kids are placed together until such time as the kids are able to follow the mothers in grazing.

Mocha Coffee--Arabian coffee.

Mochilla--A large piece of skin or leather covering for a horse saddle. In the last century, mochillas fitted with pockets called continas were used in the western United States by pony express riders.

Moderate Live Virus--A virus that has been changed by passage through an unnatural host, such as passing hog cholera virus through rabbits, so that it no longer possesses the disease-producing characteristics but so that it will stimulate antibody production and immunity when injected into susceptible animals.

Modified Milk--(1) Cow's milk altered to a composition suitable for the special needs of infants. (2) A mineral-vitamin fortified milk for general beverage use. (Sometimes applied to homogenized milk.)

Modifier--(1) Any element that is added to, or taken from a substance that alters its normal appearance or function. (2) A substance that can alter the course of carcinogenesis.

Modifying Gene--A gene that changes the expression of the chief gene, or genes, controlling a character.

Modoc--Wool sheared from range lambs that had been feedlot fed in the central states.

Mohair--(1) The long, lustrous hair from the Angora goat. (2) Cloth made from the hair of Angora goats. See Angora Goat.

Mohair Cincha--A western cinch or saddle girth made of mohair.

Moisture--(1) The total amount of water in any plant or animal product. (2) Any form of water. (3) The total amount of water (exclusive of that in chemical combinations) in the soil, both that which is available and that unavailable for plant growth.

Moisture Pan--A vessel in an incubator that contains the water that provides the humidity necessary for incubation of eggs.

Molar--In mammals, one of the large back teeth with ridged or rounded surface specially adapted for grinding.

Molascuit--A cattle feed made from sugarcane bagasse and molasses. Molasses Feed-An animal feed, usually a commercial mixture in which molasses is an ingredient; used as a substitute for grain because of its palatability and because it is a cheap source of readily digested carbohydrates.

Molasses Silage--Legume or grass silage to which specified amounts of molasses, such as blackstrap, are added to aid the proper fermentation, increase the carbohydrates, improve palatability, etc.

Mold--(1) A form containing a cavity into which material is poured or pressed to achieve a special shape and design; e.g., molds for Edam and Gouda cheese, butter, ice cream, etc. (2) Any soft, humus soil. (3) Fungi distinguished by the formation of a mycelium (a network of filaments or threads), or by spore masses; usually saprophytes. However, various kinds may do serious damage to fruits, hay, grain, growing crops, and ornamental plants. Also spelled mould. See Compost, Downy Mildew, Mildew, Powdery Mildew.

Mold Poisoning--Harmful effects upon animals from eating certain moldy feeds. The poisoning may be due to the degree of moldiness, or to prolonged feeding when less harmful molds are involved. With horses, the effect may be a nervous disease resulting in blindness and a staggering gait.

Moldiness--In judging and grading cheese, any defect due to the presence, or previous presence, of undesirable molds.

Moldy--Infected by molds (fungi); designating objectionable quality due to appearance or odor, flavor, toxicity, caused by molds.

Molecule--The smallest part of a substance that can exist separately and still retain its chemical properties and characteristic composition; the smallest combination of atoms that will form a given chemical compound.


Molt--The casting off of old feathers, skin, horns, etc., before a new growth, as with the normal annual renewal of plume of adult chickens, turkeys, etc. Also called the castoff covering (British); moult.

Molting--An interruption of egg laying, either natural or forced.

Molybdenosis--A disease of domestic animals caused by ingesting an excessive amount of high-molybdenum forage. General weakness and diarrhea are the symptoms. So far molybdenosis has not been reported in people. See Teart.

Monday Disease--See Azoturia.

Moniliasis--An infectious mycotic disease of the mouth and especially of the crop of domestic poultry and of the mucous membranes of dogs, calves, colts, and humans. The causative fungus is Candida albicans. Also called thrush crop mycosis.

Monkey Mouth--A condition in animals in which the lower teeth protrude over and beyond the upper teeth.

Mono--Single; only one.

Monoestrous Animal--An animal that has only one estrous (heat) cycle each year.

Monogastric--Refers to an animal that has only one stomach or stomach compartment, such as swine.

Monohybrid--A hybrid whose parents differ in a single character.

Monohybrid Cross--A cross between two individuals that are heterozygous for one pair of genes; an example is Aa ??Aa.

Monophagia--(1) Eating only one kind of food. (2) Eating only one meal a day.

Monophagous--Feeding upon only one kind of food, for example one species or one genus of plants.

Monophagous Parasite--A parasite restricted to one species of host.

Monorchid--A male with one testis in the scrotum and one inside the abdominal cavity.

Monotrophic--Designating bees that visit only one kind of flower.

Monoxenous Parasite--A parasite that requires only one host for its complete development.

Moon-blind--Referring to a horse suffering from periodic ophthalmia.

Mop Up Bull--A bull that is put into a pasture with cows that have been artificially inseminated. The purpose is to breed those that are not pregnant.

Morbidity--The condition of being diseased, or the incidence or prevalence of some particular disease. The morbidity rate is equivalent to the incidence rate.

Morgan--An American breed of light, general-purpose horse developed principally as a riding horse. Individuals stand 14.2 to 16 hands high and weigh 800 to 1,200 pounds. Standard colors are bay, brown, black, and chestnut with white markings.

Morphogenesis--The developmental history of organisms or of their parts.

Morphology--(1) A branch of biologic science that deals with the forms, rather than the functions, of plants and animals. (2) Pertaining to pedology or soil science, the study of soil horizons and their arrangement in profiles. (3) Pertaining to land surfaces, the shape or configuration of physical features.

Morrison Standard--A feeding standard formulated by F.B. Morrison of the University of Wisconsin, author of Feeds and Feeding, which is adapted to practical feeding conditions and is used extensively.

Mortality--The number of overall deaths, or deaths from a specific disease, usually expressed as a rate; i.e., the number of deaths from a disease in a given population during a specified period, divided by the average number of people or animals exposed to the disease and at risk of dying from the disease during that time.

Mossy--(1) Designating irregular, dark markings that spoil an otherwise desirable color contrast on the feathers of domestic birds. (2) Covered with moss.

Mossy Horn--(1) An animal horn that has become wrinkled and scaly from age. (2) A term designating a very old animal.

Mossy-coated--In the show ring, designating a beef animal that has hair of a solid color containing darker mottlings.

Most Probable Producing Ability (MPPA)--An estimate of a cow's future productivity for a trait (such as progeny weaning weight ratio) based on her past productivity. For example, a cow's MPPA for weaning ratio is calculated from the cow's average progeny weaning ratio, the number of her progeny with weaning records, and the repeatability of weaning weight.

Motes--(1) In cotton ginning, immature seed and particles of trash. (2) Burs, etc., found in wool. Also called moits.

Mother Culture--In dairy bacteriology, milk or a liquid milk product introduced into a control culture of actively growing bacteria, specific for the production of a definite fermented product.

Mothering Ability--In beef cattle selection, the ability of a cow to wean a large, fast-growing calf. Weaning weight is highly correlated to the dam's ability to produce milk.

Motile--Self-propelling, as spores or sperms, by means of cilia or elaters.

Motility--Active movement in artificial insemination of the sperm in a male's semen.

Mottle--(1) A spot or blotch of a color different from the mass color of a surface, as a mottle caused by a viral disease of a plant. (2) Color difference on a mass of moderately poorly drained soil.

Mottled--(1) Designating bird feathers marked with white tips at the ends or spotted with colors or shades at variance with the ideal. (2) Irregularly marked with spots of different colors, as a mottled soil, butter, etc.

Mottling--A soil mass containing many colors due to poor internal drainage. The colors may be gray, yellow, and/or red in random patterns.

Moufflons--A breed of wild sheep believed to be ancestors of some present-day domestic breeds.

Mould--See Mold.

Moult--See Molt.

Mount--(1) A horse for riding. (2) A riding seat. (3) To copulate, as a male animal. (4) To get into a saddle on the back of a riding horse. (5) A mountain, or a high hill. Used always instead of mountain before a proper name.

Mountain Fever--See Equine Infectious Anemia.

Mountain Oyster--The testicles of a lamb, pig, or calf that is used for human consumption.

Mounting Block--Any block of wood, etc., that is designed as a step for easier mounting of a saddle horse.

Mouse Dun--A coat color of some animals, especially horses. It is a dun color imposed on black, seal brown, dark mahogany bay, or dark liver chestnut giving a smoky effect. Sometimes called smoky.

Mouth Speculum--An instrument used by veterinarians for holding an animal's mouth open to facilitate inspection of the mouth, dental work, or the administering of medicines. Also called jaw spreader.

Mouthing--Determining the approximate age of a horse by examining the teeth.

Mouton--A modern fur made by a chemical treatment and processing of sheep pelts carrying designated lengths and qualities of wool on the skin.

Mow-burned--Designating hay that has been damaged or altered by heating and fermentation in the mow. Also called mowburnt.

Mozzarella--Semisoft, mild Italian cheese used in pizza and other cooked foods.

Mucoid--Resembling mucus.

Mucopurulent--A body discharge that contains both mucus and pus.

Mucor--A widely distributed genus of molds of the family Mucoraceae, mainly saprophytic species, abundant in soil, decaying vegetable matter, dung, etc. Some are capable of converting starch into sugar, and thus important industrially. Probably the most frequently met and most troublesome species is the black bread-mold, Rhizopus nigricans, which appears wherever starchy substances are found, as on stale bread, and which causes a watery rot of strawberries, and peaches, a soft rot of roots of the sweet potato, and even rot in the tubers of the Irish potato when they have been weakened by cold or bruises or other unfavorable conditions. A few species of Mucor are weak parasites in animal tissues. Choanephora mold attacks and destroys the blossoms of squash and pumpkin (Cucurbita) and of Hibiscus..

Mucosa--See Mucous Membrane.

Mucous Membrane--A form of epithelial tissue that secretes mucus and lives in the body openings and digestive tract.

Mucus--Viscid, watery secretion of the mucous glands, composed of water, mutin, inorganic salts, epithelial cells, leucocytes, and granular matter.

Mud Fever--(1) A variety of erythema that attacks the heels and coronets of horses' feet, causing irritation. It may develop during wet weather from mud caked on the feet. (2) In some sections of the United States, a popular term for avian monocytosis of turkey.

Muffs--The whiskerlike crop of feathers on either side of the face below the eyes of certain fowls.

Mugging--Bulldogging or throwing a calf.

Mule--(1) The hybrid offspring of a jackass and a mare; used as a draft animal. Mules have advantages over horses in that they are more resistant to heat, require less care in feeding, have fewer digestive disturbances, are less nervous, and more surefooted than the horses. (2) The spinning machine used for the manufacture of woolen yarn.

Mule Foot--A condition in which cloven-footed animals such as wine or cattle have no parting of the hoof. The hoof resembles a horse or mule foot. The cause is genetic.

Mule Jack--A jack bred to a mare in contrast to one used for jack stock perpetuation. See Jennet, Jack.

Muley (Mulley)--A cow without horns; generally, any polled or hornless beef or dairy cattle.

Multi--A prefix meaning many, as multiovulate, many-ovuled.

Multiparous--(1) Giving birth to more than one offspring at a time. (2) Having had several offspring resulting from more than one pregnancy.

Multiple Alleles--More than two different genes that can occupy the same locus on homologous chromosomes.

Multiple Cropping--In favorable climates, the growing of two or more crops consecutively on the same field in a single year, such as corn and wheat; soybeans and wheat.

Multiple Farrowing--Arranging the breeding program so that groups of sows farrow at regular intervals throughout the year.

Mummification--(1) In animal reproduction, the drying up and shriveling of the unborn young. (2) In fruit, drying and shriveling caused by the brown rot pathogen.

Mungo--Wool fibers recovered from old and new hard worsteds and woolens of firm structure. The fibers are less than one-half inch in length, and owing to their reduced spinning and felting quality, their use is restricted largely to the cheaper woolen blends. The mungo fiber is usually shorter than the shoddy fiber.

Munsell Color Standards (Munsell Notation)-A color designation system that specifies the relative degrees of the three variables of color: Hue, value, and chroma. The standards may be used in precise comparison of colors of soils, or in standardizing agricultural products: e.g., prime cottonseed cake is 10YR5/5, which means yellow-red with value = 5, and chroma = 5.

Murrain--(1) A disease of Irish potatoes. Murrain is a term applied to the historically famous potato blight disease in Ireland. (2) See Cattle Tick Fever.

Murray Grey--A breed of beef cattle developed in Australia by the systematic crossing of Shorthorn and Angus. They are polled and silver in color with black skin pigmentation.

Murrina--An equine disease caused by Trypanosoma hippicum, a protozoan parasite in the blood. The affected animals are emaciated and feverish and may have anemia, conjunctivitis, edema, and paralysis of the hind legs.

Muscle Contracture--A congenital, lethal disease of animals, characterized by stiff joints. The young pigs, lambs, and calves are sometimes affected in the womb and are dead at birth.

Muscovite--A mineral, a member of the mica group, the common white, green, red, or light brown mica of granites, gneisses, and schists. Monoclinic crystal structure. See Mica.

Muscovy--A domesticated, ducklike waterfowl that originated in South America. It is commonly classed as a duck but is of a distinct race and when crossed with other races of ducks its progeny are sterile. The period of incubation for eggs is thirty-five instead of twenty-eight days, as with other ducks. They differ also in that the head and face of both male and female are covered with coruncles. There are two varieties: white and colored.

Muscular Stomach--See Gizzard.

Mushy--Wool that is dry and wasty in manufacturing.

Musk Glands--Glands that secrete an odor as a secondary sexual characteristic, and in the male goat are mainly situated just in front of the horns.

Musquash--The dressed skin or prepared fur of the American muskrat. See Muskrat.

Mustang--(1) In the southwestern United States, a wild descendant of the Spanish horse, generally smaller and inferior to the domestic Spanish horses. (2) A small domestic pony that is largely of Spanish breeding. (3) A range horse that is somewhat wilder than the average. Also called mestang. See Feral.

Mustang Cattle--Wild cattle (southwestern United States).

Mustiness--An offensive, pungent odor caused by molds.

Musty--Designating a defect of milk, cream, butter, or ice cream that has an offensive odor, as that imparted by molds or by a damp, unventilated cellar or basement.



Mutagen--A chemical, physical and/or radioactive agent that interacts with DNA to cause a permanent, transmissible change in the genetic material of a cell. See Teratogen.

Mutant, Mutation--A variant, differing genetically and often visibly from its parent or parents and arising rather suddenly or abruptly. Mutation can occur naturally or can be induced by radiation (x rays, gamma rays, or thermal neutrons) or chemically by ethyldemethyl sulfate.

Mutterkorn--See Ergot.

Mutton--The flesh of a grown sheep (at least one year old) as opposed to lamb (less than one year old).

Mutton Buck--A male mutton sheep.

Mutton Goat--A goat sold for its flesh.

Mutton Sheep--Any of several breeds of sheep developed primarily for their meat.

Mutton-withered--An animal that is low in the withers, with heavy shoulder muscling.

Mutualism--Dependency of two organisms upon each other. Among insects, an example is furnished by the cornfield ant and the corn-root aphid.

Mutualistic--Designating a mutually beneficial relationship between organisms; symbiosis, e.g., Rhizobium bacteria and compatible legumes.

Muzzle--(1) The projecting part of an animal's head, comprising the nose, mouth, and jaws, as of a cow, horse, or dog. (2) To cover the muzzle of an animal to prevent eating, biting, etc.

Mycology--The science dealing with fungi.

Mycoplasma--An organism that is between a virus and a bacteria in size. It may possess characteristics of a virus and is not visible under a light microscope.

Mycosis--A disease caused by the growth of fungi in plants or animals.

Mycotic Disease--A disease caused by a fungus.

Mycotic Lymphangitis--A glanderslike horse disease that affects the skin, superficial vessels and lymph nodes. It is attributed to a yeastlike fungus, Cryptococcus farciminosus, family Torulopsidaceae. Also called epizootic lymphangitis, lymphangitis epizootica, African glanders, Japanese farcy, Neopolitan farcy.

Mycotoxins--Chemical substances produced by fungi that may result in illness and death of animals and humans when food or feed containing them is eaten.

Myiasis--A disease due to the presence of fly larvae in warm-blooded animals.

Myocarditis--Inflammation of the muscular walls of the heart or myocardium.

Myometrium--The muscular layer of the uterus that brings about the expulsion of the fetus at parturition.

Myricin--The waxy portion of beeswax remaining after the major portion has been dissolved in alcohol.

Myxedema--A disease resulting from insufficient secretion of the thyroid gland. Not common among animals, it is present in some calves of the Dexter breed.

Myxomatosis--A viral disease of the pox group, transmitted by vectors, nonlethal to the South American rabbit, its natural host, but lethal to most European rabbits. Tested by the Commonwealth Scientific and Industrial Research Organization as a method of European rabbit control in Australia and in many European countries in the 1950s. The virus was successful in killing unwanted wild rabbits.
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Title Annotation:Part 3: H-M
Publication:Delmar's Agriscience Dictionary
Article Type:Definition
Date:Jan 1, 2000
Previous Article:Part 1 Animal science.
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