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Like a foreign language, terms unique to equine science can be baffling to the newcomer. When individuals travel to a foreign country and want to do business, they are expected to know the language of the country. The same is true for the individual wanting to learn about horses. Indeed, the term glossary means obscure or foreign words of a field. Successful individuals use the glossary and learn the language. Words not found in the glossary may be listed in the index or defined within a chapter of the book.


abdomen--The part of the body between the thorax and the pelvis (the belly region).

abdominal worm--Nematode parasite that lives in the abdominal cavity.

abductors--Muscles that move a limb away from the center plane of the horse.

abortion--Premature termination of a pregnancy.

abscess--A localized collection of pus in a cavity formed by disintegration of tissues.

absorption--To take in by various means.

accounting--A system of recording, classifying, and summarizing commercial transactions in terms of money.

accrual accounting--An accounting system in which expenses are considered expenses when they are committed and income is counted as income when it is earned. This includes changes in inventory.

acid solution--A solution with pH less than 7 (for example, a mixture of equal parts of vinegar and water).

active immunity--A long-lasting immunity that is achieved when an animal is challenged and stimulated to produce its own antibodies.

acute--Refers to a disease that runs a short, severe course. additive genes--The members of a gene pair that have equal ability to be expressed.

adductors--Muscles that pull a limb toward the center plane on the horse.

adenosine triphosphate (ATP)--The universal energy-transfer molecule.

adhesion--The abnormal union of surfaces normally separated by the formation of new fibrous tissue resulting from inflammation.

adipose--Fat tissue.

adrenal cortex--Outer portion of the adrenal gland producing corticosteroids.

adrenal medulla--Center portion of the adrenal gland producing epinephrine and norepinephrine.

aerobic--Occurring only in the presence with oxygen.

afferent--Nerves that carry impulses toward the central nervous system.

agglutination--A clumping together of living cells caused by an antibody.

aglactic mare--A mare not producing milk in adequate quantities.

agonistic behavior--Combative behavior.

aids-The means by which a rider communicates with a horse (e.g., hands, legs, voice, and seat).

air requirements--Refers to the ventilation necessary for the size and number of animals in a building.

albino--A horse with the dominant W allele, which lacks pigment in skin and hair at birth. The skin is pink, the eyes brown (sometimes blue), and the hair white. Such a horse is termed white.

alkaline solution--A solution with pH greater than 7 (for example, a spoonful of baking soda in a pint of warm water).

allantois--Embryonic/fetal membrane.

alleles--The alternative form of a gene having the same place in a homologous chromosome, or genes on the same location of a pair of homologous chromosomes.

allelomimetic behavior--Mimicry behavior.

allergy--Heightened sensitivity to a particular substance that does not affect the majority of the group.

alveoli--The sac in the lung where the exchange of oxygen and carbon dioxide occurs.

amble--A lateral gait, distinguished from the pace by being slower and more broken in cadence. It is not a show gait.

amino acids--The building blocks that make up the body's protein.

amniotic fluid--Fluid contained within the innermost of the fetal membranes, just outside the fetus.

anaerobic--Occurring without oxygen.

anaphylactic shock--An extreme antigen-antibody reaction.

anatomical--Refers to the structural parts of the body and the relation of its parts.

androgens--Hormones that maintain and control masculine characteristics.

anemia--A condition in which blood is deficient in red blood cells.

anestrus--The time when a mare does not cycle or have a heat period; usually occurs in the winter.

aneurysm--When a blood vessel is dilated and then fills with blood.

angle of incidence--Refers to the angle at which the incisor teeth meet.

angulation--The amount of angle.

ankle--The joint connecting foot and the leg.

annuals--Plants that complete their life cycle from seed in one growing season.

anoplocephaliasis--A disease of yearlings at pasture caused by tapeworms.

anterior--Forward (in space) or toward the head.

anthelmintics--Drugs used to treat worms in horses. antibiotics--Substances with the capacity to inhibit the growth of or kill microorganisms.

antibodies--Large protein molecules that destroy bacteria, yeast, some viruses, and toxins.

antigens--Substances that, when introduced into an organism, induce an immune response consisting of the production of a circulating antibody.

anti-inflammatory--Drugs that can be used to lessen pain and decrease inflammation.

antiseptic--An agent used in the treatment of wounds or disease to prevent the growth and development of germs.

anus--The exterior posterior opening of the digestive tract.

anvil--A heavy block of iron or steel on which metal may be forged.

aorta--The main vessel that carries blood to all bodily organs except the lungs.

apprenticeship--A job that involves working under the supervision of a professional for a variable amount of time. This type of job may or may not include a salary.

Archeohippus--One of the early ancestors of the modern horse.

arteries--Vessels that carry blood from the heart.

arthritic--Inflammation of a joint.

articulation--Where the joints come together.

artificial insemination (AI)--Introducing sperm cells into the female reproductive tract by means other than natural service.

ascarids--Part of the large groups of parasites known as roundworms.

as-fed basis--Indicates that the amount of nutrients in a feed or diet is expressed in the form in which it is fed.

assets--The property or resources owned and controlled by a business.

assimilation--The transforming of digested foods into an integral and homogenous part of the solids or fluids of the organism.

atrophy--A wasting away or shrinking of muscle.

atropine--An alkaloid compound used as an antispasmodic.

auditory--The sense of sound.

autonomic nervous system--The system that is concerned with control over the digestive system, eyes, blood vessels, glandular products, and other automatic functions.

axon--A nerve cell that conducts impulses away from the cell body.

azoturia--A disease common to draft horses and characterized by the passing of red or brown urine.


Babesia--Small protozoan parasites that occur in red blood cells. Ticks are the intermediate hosts.

baby teeth--Temporary teeth.

back--Trotting in reverse.

bacterial spore--A microscopic form of a bacterium that is very resistant to damage.

bad mouth--A malocclusion where the top and bottom teeth do not meet.

bag up--A term used to describe the development of the mammary glands near the time of parturition.

balance--The ability of a horse to coordinate action, go composed, and be in form.

balance sheet--Statement of the assets owned and liabilities owed in dollars. It shows equity or net worth at a specific point in time.

bald face--A wide white marking that extends beyond both eyes and nostrils.

banding--A style of manes seen in Western show horses. Manes are sectioned and fastened with rubber bands.

Bang's--Another name for brucellosis.

barn sour--A horse that will run back to the barn.

barren mare--Mare that has not had a foal.

bars--(1) The structure that keeps the hoof wall from overexpanding. It is a support structure that angles forward from the hoof wall. (2) The gap between a horse's incisors and molars. (3) Side points on the tree of a saddle.

basal metabolism--Minimal energy requirements to maintain vital body processes.

base-narrow toe-in--Narrow at the feet.

base-wide toe-out--Wide at the feet.

beat--Refers to the time when a foot--or two feet simultaneously--strike the ground. Beats may or may not be evenly spaced in time.

bedding--A cushioning material for an animal.

bench knees--Lateral deviation of the cannon bone.

benzimidazole--A classification of antiparasitic drug.

birth date--For racing or showing events, the foal's birthday is considered as January 1, regardless of the actual month it was born.

bishoping--Artificial altering of the teeth of an older horse to make it sell as a young horse.

bit--The part of the bridle that is put in the horse's mouth and used to control the animal.

biting--Horses have several reasons for biting; for example, when too much pressure is applied in grooming or during cinching the saddle girth. They may also bite in self-defense.

blacksmith--A person who trims and puts shoes on horses' feet.

blastula--A hollow ball of cells, one of the early stages in embryological development.

blaze--A type of coloring on the face of the horse.

blemish--A blemish differs from an unsoundness in that it is unattractive, but does not and is not apt to interfere with the horse's performance. It is usually an acquired physical problem that may not make the horse lame but may interfere with the action of the horse. A blemish does not have to be an unsoundness.

blindness--This is characterized by cloudiness of the cornea or complete change of color to white. Pale blue, watery eyes may indicate periodic ophthalmia (moon blindness).

blistering--Application of an irritating substance as treatment for a blemish or unsoundness. Blistering increases the blood supply to the site of the blister and induces more rapid healing.

bloom--A shiny coat for show horses.

boarding contract--Agreement between the owner of a horse and the owner of the stable.

bobtailed hackney--A large horse used to pull carriages.

bog spavin--A soft fluctuating enlargement located at the upper part of the hock and due to a distention of the joint capsule.

bolt--To eat rapidly; to startle.

bone spavin (jack spavin)--A bony enlargement at the base and inside back border of the hock. It may fuse bones and render joints inarticulate.

boot--A device that can be applied to the foot to prevent it from injuring the elbow.

bots--The larvae of an insect, the botfly.

bowed tendon--A serious discrimination involving any or all of a group of tendons and ligaments, but usually the superflexor tendon, the deep flexor tendon, and the suspensory ligament. It is caused by severe strain and wear and shows up as a thickened enlargement of the tendon that occupies the posterior space in the cannon region between the knee and ankle or between the hock and ankle.

bowline knot--A type of knot that will not slip.

braid puller--A piece of baling wire bent to form a long, narrow loop.

braiding--A style of manes seen in hunters and jumpers. Manes are sectioned and braided into small, neat braids.

break-even analysis--Determining where income is equal to the total of the fixed costs and variable costs of doing business.

breast collar--A collar sometimes used to keep the saddle in place.

breeching--The part of a harness that passes around the rump of a draft horse.

breed--(1) To produce young; a particular sort or kind of animal. (2) A group of horses selected for their common ancestry and common characteristics.

breed registries--Organizations that track horses breeding true or with a common ancestry.

breeding true--This means the offspring will almost always possess the same characteristics as the parents.

bridle path--A trail or path designated for use by horses and riders. Also, a space clipped in the mane just behind the ears for the crownpiece of a bridle or halter. The bridle path should be 2 to 8 inches long, depending on the breed of the horse.

bronchi--The two main branches of the trachea going to the lungs.

bucked shins--Temporary unsoundness characterized by inflammation of the bone covering along the front surface of the cannon bone.

buck-kneed--Standing with knees too far forward.

bulk--Excessive amounts of fiber or water.


calcification--Replacement of the original hard parts of an animal by calcium carbonate.

calf-kneed--When the knees tend to bow inward.

Calippus--One of the early ancestors of the modern horse.

calks--Grips on the heels and the outside of the front shoes of horses, designed to give the horse better footing and prevent slipping.

camped-out--A condition where the leg is too far back and behind the plumb line. Usually the whole leg is involved and the plumb line is at or in front of the toe instead of behind the heel.

camped-under--The opposite of camped out.

canines--The pointed teeth beside the incisors.

cannon bone--The bone extending between the knee or hock and the fetlock joint in horses.

canter--A slow, restrained, three-beat gait in which the two diagonal legs are paired, thereby producing a single beat that falls between the successive beats of the other unpaired legs.

capillary--The smallest blood vessel that connects the arteries and veins.

capillary refill--The number of seconds it takes for the color to return to an area of the horse's gum that has been pressed with the thumb once the thumb is removed. One to 2 seconds is normal.

capital--The amount of money that can be obtained through borrowing or selling assets; it is used to promote the production of other goods.

capped elbow--A blemish at the point of the elbow, also called shoe boil. It is caused by injury from the shoe when the front leg is folded under the body while the horse is lying down.

capped hocks--An enlargement at the point of the hock; it is usually caused by bruising.

carbohydrates--Any of a group of neutral compounds composed of carbon, hydrogen, and oxygen including the sugars and starches. They are used immediately for growth or stored for future use.

carnivores--Animals feeding or preying on animals, eating only animal food.

carotene--A compound from which vitamin A is synthesized.

carriage traces--Straps, chains, or ropes of a harness, extending from the collar (specifically the hames) to the vehicle or load.

cartilage--A translucent elastic tissue that composes most of the skeleton of embryos and very young vertebrates. Most cartilage is replaced by bone.

cash-basis accounting--An accounting system in which income is recorded as income when it is received and expenses are recorded as expenses when they are paid.

cash flow--Actual cash levels for a business.

caslick--A procedure in which the vulva is sutured to prevent infection.

catalyzed--When the chemical reaction rate is increased.

catheter--A slender tube inserted into a body cavity for drawing off or administering fluids.


cavalry--Originally, a military force mounted on horseback; its main duties include observing and reporting information about the enemy, screening movements of its own force, pursuing and demoralizing a defeated enemy, maintaining a constant threat to an enemy's rear area, striking suddenly at detected weak points, turning exposed sides, and exploiting a break in the enemy's lines.

cecum--The blind pouch that forms the beginning of the large intestine.

cell--The smallest unit of life.

centaur--Mythical Greek race that were imagined to be men with the bodies of horses.

center of gravity--The centered mass of the horse, most commonly located in the middle of the rib cage just caudal to the line separating the cranial and middle thirds of the body. The forelimbs bear 60 to 65 percent of the body's weight because the center of gravity is located more cranially.

centers--Another name for centrals.

centrals--First incisor teeth.

centrioles--Two cylindrical bodies, located near the nucleus, that play a part in cell division.

cerebellum--The part of the brain responsible for control of voluntary muscular movement.

cerebrum--The part of the brain, anterior to the brain stem, responsible for memory, intelligence, and emotional responses.

cervix--The outer end of the uterus.

chestnuts--Horny, irregular growths on the inside of the horse's legs. On the front legs, they are just above the knee. On the rear legs, they are toward the back of the hock. Chestnuts are like human fingerprints--no two are alike, and they do not change in size or shape throughout the horse's adult life.

chiggers--The larval stage of harvest mites; they affect horses' feet and muzzles.

chip fractures--Occur in several different places but are most common at the knee. They are small fractures that break off one of the bones in the knee. They are usually caused by high amounts of concussion and stress on the knee and are seen most frequently in racing horses.

chromatids--Because of the syntheses during the interphase stage of mitosis, each chromosome consists of two sister chromosomes (chromatids) that are identical in their structural and genetic organization. They become visible when mitosis begins.

chromosomes--Microscopic structures, found in the nucleus of cells, that carry the genes.

chronic--Continuing a long time.

cinch--The part of a Western saddle used to hold it onto the horse under the girth area.

classes of horses--The classification of horses according to their use.

clinch cutter--Tool used to remove used horseshoes.

clinching block--A tool used to remove old horseshoes.

club foot--In this condition, the foot axis is too straight and the hoof is too upright.

cob--A close-knit horse, heavily boned, short coupled and muscular, but with quality; not so heavy or coarse as to be a draft animal. A cob is usually small, standing under 15 hands.

cocked ankles--These may appear in front but are more common in hind legs. Severe strain or usage may result in inflammation or shortening of the tendons and a subsequent forward position of the ankle joints.

coffin bone--The bone of the foot of a horse, enclosed within the hoof.

coldblood--A horse of draft horse breeding.

cold-fitted--Horseshoes that are applied to the feet without heat.

colic--A broad term that describes a horse showing abdominal pain. Has a number of causes but generally indicates pain in the digestive tract.

collar--Part of a draft horse harness fitted over the shoulders that helps to take the strain when a load is pulled.

collateral--Property, savings, stocks, and so forth deposited as security additional to one's personal or contractual obligations.

collected--Describing a horse that has full control over its legs at all gaits and is responsive to the cues of its rider.

color breed--Color breeds do not breed true colors, for example, albinos, paints, Appaloosas, buckskins, white, cream, or spotted.

colostrum--The first milk secreted by a mare just before and the first day after foaling. It is high in antibodies that protect the newborn against infectious diseases.

colt--A male horse up to 3 years of age.

combined immunodeficiency disease--A condition in which an animal is deficient in cells of the immune system.

commissures--A band of nerve fiber connecting the two halves of the brain or spinal cord or paired ganglia.

competencies--Abilities or capabilities of employees.

compost--Piling organic matter in a way that encourages decay and decomposition.

concentrates--Classification of feedstuffs that are high in energy and low in crude fiber.

conception--The act of becoming pregnant.

condition score--A subjective score given to a horse based on its overall body fat.

conditioned response--Response to a stimulus that is learned.

confinement--Refers to a situation in which a horse lives in an enclosed stall, versus free in a paddock or pasture.

conformation--How the horse is shaped according to type and/or breed.

congenital--Condition that exists at birth; acquired during the prenatal period.

Conquistadors--Early Spanish explorers and warriors.

conservative treatment--A more reserved treatment for bone fractures in horses. The treatment consists of stall confining, hand walking, and anti-inflammatory drugs to reduce pain and swelling.

constrict--To draw together or render narrower.

contouring--Being able to shape something to fit the contours of something else.

contracted feet--This is caused by continued improper shoeing, prolonged lameness, or excessive dryness. The heels lose their ability to contract and expand when the horse is in motion.

contracted heels--An abnormal contraction of the hoof wall at the heels.

contraction--A complex interaction of many parts of the nervous system and the muscular system. It is controlled by the nervous impulses received by the muscle cells.

cooler--A large square of wool or acrylic material used to cover a horse from head to tail. A cooler is useful for cooling out a horse.

cornea--The transparent part of the coat of the eyeball that covers the iris and pupil.

corners--The third incisor.

corns--Reddish spots in the horny sole, usually on the inside of the front feet, near the bars. Advanced cases may ulcerate and cause severe lameness.

coronary band--Area where the hoof meets the leg; it produces the hoof wall.

coronary vessels--The blood vessels that provide nourishment to and encircle the heart like a crown at the juncture of the atria and the ventricles and send branches to both structures.

coronet--The dividing line between the hoof and the leg of a horse.

corporation--A body of people recognized by law as an individual person having a name, rights, privileges, and liabilities distinct from the individual members.

corpus hemorrhagicum--The bloody spot on the ovary immediately after ovulation that becomes a corpus luteum.

corpus luteum--The gland formed on the ovary following ovulation that produces the hormone progesterone.

corticosteroids--Hormones from the adrenal glands.

cowlicks--Permanent hair whorls that cannot be brushed or clipped out. They are located mainly on the forehead and neck.

cracks (quarter, toe, heel)--Associated with a hoof wall that is too long and has not been trimmed frequently enough. They can also develop with horses that are in rain and mud for long periods of time. The mud draws water out of the hoof wall and when the hoof dries it often cracks.

cradle--A device useful in preventing an animal from licking or biting an injured area.

cranial--Relating to the cranium, the part of the skull that encloses the brain.

creative thinking--Ability to generate new ideas by making nonlinear or unusual connections or by changing or reshaping goals to imagine new possibilities; using imagination freely to combine ideas and information in new ways.

creep feeding--Feed supplied to the foal in an area unavailable to adult horses.

crescent--Shaped like the moon in its first quarter.

crestfallen--A heavy neck that breaks over and falls to one side.

cribbing--When horses grasp an object (e.g., a feed box edge or manger) between their teeth and apply pressure, gradually gnawing the object away if it is not metal.

cross-firing--The same as forging in a pacer; occurs when the inside of the near fore and hind leg (or the reverse) strike in the air as the stride of the hind leg is about completed and the stride of the foreleg is just beginning.

cross-tying--A method of using two ropes to secure a horse so the head is level.

croup--The rump of a horse.

crude protein (CP)--Total amount of protein in a feed.

crupper strap--A leather strap with a padded semicircular loop. The loop end goes under the tail and the strap end is affixed at the center of the back band of a harness or the cantle of a saddle to prevent the saddle from slipping over the withers.

cryptorchid--See ridgling.

cue--The stimulus used to train horses.

cultural diversity--Term used to describe the American workplace representing people from different backgrounds.

cups--The deep indentures in the center of the surfaces in young permanent teeth.

curb--An enlargement on the back of the leg, just below the hock. It is caused by trauma to the plantar ligament that causes the ligament to become inflamed and then thickened.

curb bit--A bit that works with leverage action on a horse's mouth. A curb bit must have shanks and a curb strap or chain.

curb chain--Used in combination with a curb bit. It acts against the chin groove to produce a painful pressure.

cut-back--A saddle cut back at the withers.

cytoplasm--The material that lies within the cell and contains several organelles and granules in suspension.


dam--The female parent of a horse.

dam's produce--Offspring from a particular dam.

data sheet--Similar to a resume; contains pertinent information about a potential employee.

deciduous--Temporary teeth.

deep flexor tendon--The inner part of the leg, responsible for extension of the foot as it progresses through a stride.

defecation--Release of feces from the bowel.

degree of finesse--Determined with gaited and parade horses by how well they "move" off their hocks.

dehydration--An abnormal depletion of body fluids.

demographic--Having to do with vital and social statistics.

dental stars--Marks on the incisor teeth appearing first as narrow, yellow lines in front of the central enamel ring, then as dark circles near the center of the tooth in advanced age.

dentition--The process of cutting teeth.

deoxyribonucleic acid (DNA)--A nuclein of complex molecular structure that is the major component of genes; it plays an important role in the gene action of chromosomes.

depressed--A state when the horse is extremely relaxed and muscles are flaccid.

dermatitis--Inflammation of the skin.

detoxification--The act of removing poison or of the effect of poison.

diaphragm--A body partition of muscle and connective tissue. Separates the thoracic cavity from the abdominal cavity.

diestrus--A period of sexual inactivity between two estrous cycles.

diffusion--The spreading out of molecules in a given space.

digesta--The food, fluids, and nutrients moving through the digestive system.

digestible energy (DE)--That portion of the gross energy in a feed that is not excreted in the feces.

digestion--The breakdown of foods in the digestive tract to simple substances that may be absorbed by the body.

digestive disturbances--Any abnormal digestive activity that causes discomfort in the animal.

dilation--Expansion of an opening, becoming wider or larger.

diluters--Any of several types of fluids used to dilute and increase the volume of semen.

directness--Also known as trueness. The line in which the foot is carried forward during the stride.

discrimination--A prejudice or partiality of unsoundness.

disease--Any condition of a horse that impairs normal physiological functions.

disinfectant--A chemical that destroys harmful microorganisms.

distal spots--Dark spots on a white coronet band.

distended--Enlarged or swollen.

domesticated--Tamed or gentled for use by man.

dominant allele--A gene that is expressed.


draft--An animal or team of animals used to pull a load; something that is drawn or pulled; or the force required to pull a load.

draft horse--A large breed of horses used for work.

dressage--A method in which, through body movements and without using hands, feet, or legs, a rider can guide a trained horse through natural maneuvers.

driving--Horses harnessed and controlled from behind.

dry matter--Indicates the part of the feed that is not water.

dry-matter basis--Method of expressing the concentration of a nutrient.

dun--Body color yellowish or gold with a mane and tail that may be black, brown, red, yellow, white, or mixed. Usually dun has a dorsal stripe, zebra stripes on the legs, and transverse stripes over the withers.

duodenum--The first part of the small intestine.

dwelling--A perceptible pause in the flight of the foot, as though the stride has been completed before the foot strikes the ground. It may occur either front or rear and is particularly common in heavy harness horses, heavy show ponies, and some saddlers.

dystocia--A retained placenta in the mare.


easy keepers--Horses that are easy to feed.

ectoparasites--Parasites that live on the outside of their hosts.

edema--Excessive accumulation of fluid in tissue spaces.

efferent--Nerves that carry impulses away from the central nervous system.

ejaculation--When the semen is expelled through the urethra.

electrolytes--Any molecular substance that, in solution, will dissolve into its electronically charged components called ions.

eliminative behavior--Behavior demonstrated by horses during defecation or urination.

embryo--The earliest stages in the development of an organism before it has assumed its distinctive form.

embryo transfer--Removal of developing embryos from one mare and their transfer to the uterus of another.

endurance fibers--These are type IIa muscle fibers used during periods of aerobic work such as jogging or long-distance riding. These fibers can use carbohydrates, fat, or protein for energy.

English--A type of riding dictated by the saddle, tack, clothing, and riding method used.

enterprise--A specific process or activity that requires a certain amount of risk to make a profit.

enterprise budget--A look at the costs and risks involved with producing one commodity or making one product.

entrepreneur--One who starts and conducts a business assuming full control and risk.

enzyme--A substance that increases the rate of a chemical reaction.

Eocene epoch--A division of geologic time following the Paleocene and ending about 37 million years ago.

Eohippus--The earliest known ancestor of the modern horse.

epimeletic behavior--Behavior indicating desire for care and attention.

epiphysitis--Swelling or inflammation around the growing points of the long bones.

epithelial--The tissues that form one or more layers of cells that cover most internal and external surfaces of the body.

Epona--An ancient Gaul goddess of horses who lovingly protected the horse and stable and also kept watch over the grooms and carters.

equine encephalomyelitis--An inflammatory disease of the brain and spinal cord.

equity--The value remaining in a business in excess of any liability or mortgage.

esophagus--A muscular tube extending from the pharynx down the left side of the neck and through the thoracic cavity and diaphragm to the stomach.

estate--One's entire property or possessions.

estrogen--Steroid hormone produced by the ovary responsible for estrus behavior.

estrus (estrous cycle)--The period of sexual excitement (heat) during which the female will accept the male in the act of mating.

euthanasia--The act of painlessly putting to death animals suffering from incurable conditions or diseases.

evaluation--Determining worth, performance, value, or conformation; appraisal.

event--A competition including dressage, stadium jumping, and cross-country jumping.

evolution--Refers to a process of continuous change from a lower, simpler state to a higher, more complex state.

expiration--Expulsion of air effected by a relaxation of muscles and a contraction of rib and abdominal muscles.

exploratory behavior--Learning from, investigating, and being attentive to the environment.

extenders--Any diluter with additives to extend the lifespan of sperm cells.

extensor--Structure used to stretch limbs out straight. The extensor tendon is attached to the front of the coffin bone.

external respiration--Consists of two movements--inspiration and expiration.

extracellular--Outside the cell.

eye worm--A parasite that lives in the tear duct and conjunctival sac of the horse's eye.


farrier--A person who cares for horses' feet, including trimming and nailing on horseshoes; a horseshoer. fatigued--Exhausted, wearied with labor or exertion. fat-soluble vitamins--Vitamins found in the fat portion of the feed and stored in the fatty tissues of the horse. feather fetlocks--Long hair growth on the fetlocks of a horse.

feathering--A fringe of hair around the horse's foot just above the hoof. Some breeds naturally have more feathering or a heavier fetlock than others.

feral--Horses that were once domesticated and have become wild.

fermentation--Decomposition of organic substances, especially carbohydrates, under anaerobic conditions. These conditions are often created by the enzymes produced by microorganisms such as yeast, molds, and bacteria.

fertilization--When a sperm fuses with an egg.

fetlock--The joint above the hoof of a horse.

fetus--The later stage of foal development within the uterus.

fibrosis--Thickening of affected skin.

filly--The name for a female horse until the age of 3.

firing--Making a series of skin blisters with a hot needle over an area of lameness.

firing marks--Where one leg strikes another.

fistulous withers--An inflammation of the withers affecting this region in much the same way as poll evil affects the poll. Source may be a bruising or bacterial infection.

fixed costs--Costs that usually do not fluctuate with an increase or decrease in production.

flanks--The fleshy part of the side between the ribs and the hip.

flat foot--Conformation that lacks the natural concave curve to the sole. Instead, the sole is flat and predisposed to more contact with the ground. Flat foot increases the chance for sole bruises and resulting lameness.

flehmen response--A particular type of curling of the lips in stallions, and many other mammals, that facilitates the transfer of odor-producing chemicals into the vomeronasal organ in the nose.

flexing at the poll--To give its head to the bit.

flexion test--Helps to determine the extent and location of a fracture or other problem of the leg.

flexor--The tendons that cause the fetlock joint to flex or bend; located behind the cannon bone.

flight--The horse's primary defense mechanism.

flighty--A nervous horse.

floating--Filing off the sharp edges of a horse's teeth.

flukes--Trematode parasitic worms that are flat and leaf-shaped.

flushing--The process of removing the embryo from a mare in preparation for embryo transfer.

foal--A young, unweaned horse of either sex.

foal heat--The heat that occurs directly after parturition. It is often not fertile.

follicle--A saclike structure within the ovary that gradually enlarges and, with one burst, releases an egg into the oviduct. Following this rupture, the corpus luteum forms.

follicle stimulating hormone (FSH)--A hormone secreted by the anterior pituitary and responsible for follicular growth and ovulation.

follow-up letter--Letter written immediately after a job interview.

Food and Agriculture Organization (FAO)--An agency of the United Nations that conducts research, provides technical assistance, conducts education programs, maintains statistics on world food, and publishes reports with the World Health Organization.

forage--Feedstuffs from the leaves and stocks of plants.

foramen magnum--The skull is attached to the first vertebra of the spine and has a large opening, the foramen magnum, through which the spinal cord passes.

Forbs--Any nongrasslike plant that is relatively free of woody tissue that an animal consumes.

forecasts--Calculations done beforehand.

forging--Striking the end of the branches or the undersurface of the shoe of the forefoot with the toe of the hind foot. This is the diagonal foot in pacers and the lateral foot in trotters.

foundation sires--All registered foals must have their ancestry traced back to the founding stallions.

foundation stock--Refers to the original animals of the breed.

founder--Also called laminitis. An inflammation of the sensitive laminae under the horny wall of the hoof. All feet may be affected, but the front feet are most susceptible.

fox trot--A slow, short, broken type of trot in which the head usually nods. In executing the fox trot, the horse brings each hind foot to the ground an instant before the diagonal forefoot.

fracture--A break or crack in a bone.

free fatty acids--Major components of lipids and fats.

free radicals--A molecule with one or two unpaired electrons that do not interact with each other; they are often very reactive and unstable.

freeze brand--An identifying mark made with copper stamps or marking rods that are cooled in liquid nitrogen or dry ice. This unalterable system of angular symbols was developed by Dr. Keith Farrell, a USDA veterinary medical officer.

frog--A triangular-shaped formation in the sole of the horse's foot. It should be full and elastic and help to bear the weight of the horse.

fulcrum--The support about which a lever turns.

full-mouthed--Refers to a horse having all of the permanent teeth and cups present.


gait--A horse's way of going, or the way of moving its legs during progression. The horse is more versatile in selecting gaits than any other four-legged animal. It uses several gaits unique to the species in a distinctive rhythmic movement of the feet and legs. A gait is characterized by distinctive features, regularly executed.

gaited horses--Horses that perform gaits other than the four natural gaits (walk, trot, canter, and gallop).

gallop or run--The run, or gallop, is a fast, four-beat gait where the feet strike the ground separately, first one hind foot, then the other hind foot, then the front foot on the same side as the first hind foot, then the other front foot, which decides the lead.

Galvayne's groove--A mark on the tooth used to determine the age of the horse.

gametes--Sex cells.

ganglia--Secondary nerve centers located chiefly along the spinal cord. They receive and dispatch nerve impulses that do not have to reach the brain (including such stimuli as heat, pain, excessive pressure, and others) but are immediately switched over to motor filaments and cause certain muscles to react instantaneously.

gaskin--The area of the horse's rear leg just below the thigh and stifle area and above the hock. They are usually heavily muscled.

gastric digestion--Chemical breakdown of foodstuffs by the stomach.

gastric juice--Digestive fluid secreted by glands in the mucous membrane of the stomach.

gastrulation--The beginning process of cell differentiation when the ectoderm, mesoderm, and endoderm are being formed.

gelding--A castrated male horse.

genes--The fundamental units of genetics that determine all the hereditary characteristics of animals.

genetic--The interaction of the genes in producing similarities and differences in individuals related by descent.

genetic variation--Differences in genetic makeup.

genome--A complete set of chromosomes.

genotype--The genetic makeup of an animal.

geologic time scale--An arbitrary chronologic sequence of geologic events, used as a measure of the age of any part of geologic time, usually presented in the form of a chart showing the names of the various rock layers, time layers, or geologic time units.

gestation--The period during which a female is pregnant.

get of sire--Offspring from a particular sire.

gingivitis--Inflammation of the gums.

girth--See heart girth.

glomeruli--Ball-shaped tiny filters, of which each kidney has several million, located in the outer portion or cortex that filter approximately 200 gallons of liquid a day, rejecting blood cells and proteins but permitting fluid salts and other chemicals, including nitrogenous wastes, to pass through.

goals--The end objectives or terminal points of a business.

goiter--An enlargement of the thyroid area.

Golgi body--A special type of membrane mixture found near the nucleus. In cells that synthesize and secrete products, the Golgi apparatus is the site of the material that is accumulated.

grade--An animal that is not registered with a specific breed registry.

granule--One of the small bodies in the cytoplasm of cells.

grease heel--See scratches.

grooming behavior--Behavior exhibited when horses care for their hair coat.

grullo--Body color that is smoky or mouse-colored. Each hair is mouse-colored. The mane and tail are black, usually the lower legs are black, and often there is a dorsal stripe.

gum disease--See gingivitis.

gymkhana--A meet for various athletic contests or games for horses, or the place where they are held.


hack--An enjoyable, good riding or driving horse, sometimes considered a small Thoroughbred in Europe or a saddlebred in America.

hackamore--A bitless bridle used in the West for training horses.

half-stocking--A white marking from the coronet to the middle of the cannon.

halter pulling--A habit that develops when a horse pulls at whatever it is being tied to.

halters--Sometimes called head collars. They are used for leading and tying a horse.

hammer--One of the tools used for horseshoeing.

hand--The height of a horse. The measurement is taken from the top of the withers to the ground; a hand is 4 inches.

hand mating--Breeding that is monitored closely by the handler.

hard at the heels--When elastic cartilages under the skin that serve as part of the shock-absorbing mechanism ossify they are firm but movable inward and outward by the fingers.

hard keepers--Horses that need more feed per unit of body weight.

hard-keeping--A horse that has a very hard time putting or keeping weight on its body.

hard mouth--Term used when the membrane of the mouth where the bit rests becomes toughened and the nerves deadened because of continued pressure from the bit.

heart girth--Also called girth. The circumference of the chest just behind the withers and in front of the back.

heart rate--The number of times the heart beats in a minute.

heat--Another word for estrus, or when a mare is receptive to a stallion. This time period is also when follicles develop and a mare ovulates.

heaves--An incurable respiratory disease of horses.

heaving--Caused by a loss of elasticity in the lungs, resulting from a breakdown in the walls of a portion of the air cells. There is an extra contraction of the flank muscles during expiration. It is often heard.

heel calk--Grips on the heels of the front shoes of horses, designed to give the horse better footing and prevent slipping.

herbivores--Animals that subsist primarily on the available vegetation and decayed organic material in the environment.

herd obedience--The tendency of horses to do what the group does.

heredity--Passing, or capable of passing, genetically from parents to offspring.

hernia--A protrusion of the internal organs through an opening in the body wall.

heterozygous--Having different genes for the same trait.

hierarchy--The dominance hierarchy requires that each horse recognize the other horse and determine through some initial aggressive acts (biting or kicking) and submissive acts (running away) which horse is dominant and which is subordinate.

high ringbone--A bony enlargement on the pastern bones. It occurs at the pastern joint.

hinny--A cross between a male horse, or stallion, and a female donkey (called a jennet or jenny). A hinny is similar to the mule in appearance but smaller and more horselike, with shorter ears and a longer head.

Hippocamp--One of the early ancestors of the modern horse.

hippomane--Soft, dark brown body of tissue that may be floating among the membranes of the passed placenta.

histogenesis--The process of tissue formation.

hitching post--A rail to which horses are tied.

hobble--A type of restraint used on horses in which either the front feet or hind feet (at the pastern or fetlock joints) are placed in straps to keep them from kicking or walking or wandering too far.

hock--The large joint halfway up the hind leg of a horse. Analogous to the heel of a human.

homeostasis--Maintaining a balance between all the parts.

homozygous--Having identical genes.

hoof leveler--The tool used to determine the angle of the hoof wall and check that the hoof is level to the ground.

hoof pick--A tool used for cleaning the sole, frog, and hoof wall.

hoof testers--A tool that picks up increased sensitivity, commonly over the toe, in the horse's foot.

hoof wall--A horny substance made up of parallel fibers that should be dense, straight, and free from ridges and cracks.

hormone--A product of living cells that affects the activity of cells.

horseshoeing--The process of putting shoes on horses.

hosts--The animals from which a parasite obtains food. Different parasites require different numbers and types of hosts.

hot-fitted--Horseshoes that are applied with heat.

hunters--Horses that are subjectively judged while jumping fences, or horses ridden in fox hunts.

hybrids--Animals produced from the mating of two different breeds.

hydrolyzes--Splitting a compound with the introduction of water.

hydrotherapy--The application of cold water to the affected area, usually hosing the leg.

hypercalcemia--High levels of calcium in the blood.

hyperparathyroidism--Overactive parathyroid.

hypochloremia--Low levels of chloride in the blood.

hypothalamus--An area in the brain that controls visceral activities, regulates body temperature and many metabolic processes, and influences certain emotional states.

hypothyroid--An underactive thyroid gland.

Hyracotherium--Another name for Eohippus.


ileum--The part of the small intestine that connects the jejunum to the cecum.

immune system--The system in the body that protects and fights diseases.

immunity--A condition in which an animal is resistant to a disease.

immunoglobulins--Antibodies that are members of a related group of gamma globulin molecules.


implants--Devices used to repair a fracture in a long bone.

imprinting--Imposing a behavior pattern in a young animal by exposure to stimuli; for example, exposure to humans.

incisors--Any one of the 12 front teeth.

income--Amount of money received periodically in return for goods, labor, or services.

infectiou--Diseases caused by pathogenic organisms present in the environment or carried by other animals.

infective--Capable of producing an infection.

inflammation--Redness, swelling, pain, heat, and disturbed function of an area of the body.

influenza--A contagious viral disease characterized by respiratory inflammation, fever, muscle soreness, and often a loss of appetite.

infundibulum--(1) The end of the oviduct nearest the ovary. (2) The funnel-shaped inside of the tooth.

ingestive behavior--Behavior exhibited by a horse during feeding.

inherited--Received genetically from parents.

inorganic--Something composed of substances of other than plant or animal origin.

input costs--Money required to begin production.

inspiration--Inhalation brought about by a contraction of the diaphragm and an outward rotation of the ribs.

insulin--Hormone that lowers the blood glucose and gets glucose across the cell membrane where it can be metabolized.

interdental space--The space behind the incisors and ahead of the six lower molars in each branch of the mandible.

interest--Payment for the use of money or credit.

interfering--Striking the supporting leg, usually at the fetlock, with the foot of the striding leg. Interference commonly occurs between the supporting front leg and a striding front leg or between a supporting hind leg and a striding hind leg.

intermediate host--Host of a parasite before the last host.

intermediates--Second incisor teeth.

internal respiration--The interchange of gases between the blood and the body tissues.

interphase--A long phase in the process of mitosis.

interval training--The use of multiple bouts of work interspersed with a relief interval when partial recovery is allowed.

involution--The process during which the uterus returns to normal following parturition.

ivermectin--A drug used to control parasites.


jack--Male donkey.

jejunum--The middle part of the small intestine.

jennet--A female donkey; also called a jenny.

jockeys--Professional riders of horses in races.

joint--A union of two bones.

joint capsule--The fibrous sac that encloses the entire joint.


karyotype--The entire set of stained chromosomes photographed through a microscope and then cut apart and arranged in pairs.

knocked-down hip--A fracture of the external angle of the hip bone (ilium) resulting in a lowering of the point of the hip.


laceration--A cut with jagged edges.

lactation--Producing milk.

lactic acid--The chemical produced in the body when glucose or glycogen are used for energy in the absence of oxygen.

lactose--The sugar found in milk.

laminae--The flat tissue in the sole or base of the hoof.

laminitis--An inflammation of the sensitive laminae under the horny wall of the hoof. All feet may be affected, but the front feet are most susceptible. It is characterized by ridges running around the hoof. (Also known as founder.)

large colon--The part of the digestive tract (large intestine) that is enlarged in the horse to allow time for the digestion of cellulose.

large intestine--Includes the cecum, large colon, small colon, rectum, and anus.

larvae--Newly hatched, wormlike stage in the life cycle of an insect.

larynx--The area of the respiratory tract between the pharynx and the trachea.

lateral cartilages--Elastic cartilages just under the skin and extending above the hoof on each side of the heel that serve as part of the shock-absorbing mechanism.

laterally--Toward the side.

laxative--Medicine administered to the horse to produce evacuation of the bowels.

leg cues--Signals given through the rider's legs to the horse.

legumes--Plants with the characteristic of forming nitrogen-fixing nodules on their roots, in this way making the use of atmospheric nitrogen possible.

lesions--Abnormal changes in the structure of an organ due to disease or injury. Can be internal or external.

letter of application--Sent with resume or data sheet when applying for a job.

letter of inquiry--Sent to a potential employer inquiring about possibility of employment.

liabilities--Just or legal responsibilities.

libido--Sexual drive.

lice--External parasites; they may be biting or sucking. Very host specific, they can cause serious skin irritation or anemia.

ligament--Tough, fibrous tissue that connects bones or cartilages at a joint. Ligaments can also support an organ.

light horses--Horses used primarily for riding, driving, showing, racing, or utility on a farm or ranch. A light horse is capable of more action and greater speed than a draft horse.

liniment--A preparation (mostly alcohol-based) used in treatment of mild strains, sprains, etc., as a counterirritant to increase blood flow.

Lipizzan stallions--Stallions of the Lipizzan breed, located at the Spanish Riding School, formerly in Vienna, now located in Wels, Austria.

liquidity--A business's ability to meet short-run obligations when due without disrupting the normal operation of the business.

lochia--A brown fluid found in the uterus during uterine involution following pregnancy.

longe--The act of exercising a horse on the end of a long rope, usually in a circle.

longitudinally--Running or placed lengthwise.

lope--A smooth gait, that is slower than a gallop but faster than a trot. See canter.

low ringbone--A bony enlargement on the pastern bones. It occurs at the pastern-coffin bone joint at about the level of the coronet band.

lumbar--The portion of the lower back near the loin area.

lungworm--A roundworm parasite that lives in the lung. More common in donkeys than in horses.

luteal phase--Period of time during the estrous cycle when the corpus luteum is producing progesterone.

lymph--Fluid that assists in carrying food from the digestive tract to the tissues and waste products back to the bloodstream.

lymph nodes--The gland-like bodies found in the lymphatic vessels that produce lymphocytes and monocytes.

lymph vessels--Ducts that transport lymph.

lysosomes--Small bodies that store large numbers of enzymes.


macrominerals--Minerals found in the body in large quantities, for example, calcium and phosphorus.

maiden mare--A female horse that has not been bred or had a foal.

malignant--Tending to produce death or deterioration.

malocclusion--Where the top and bottom teeth do not meet.

mandible--Lower jaw.

mange--An itching skin disease caused by parasitic mites.

mare--The name for a female horse after the age of 3.

market value--Refers to the price for which an animal might sell at auction.

mastication--The processing of chewing.

mastitis--Inflammation of the mammary glands.

maxilla--Upper jaw.

meconium--The soft, dark greenish-brown accumulation of digested amniotic fluid, glandular secretions, mucous, bile, and epithelial cells in the digestive tract during development of the foal.

megacalorie--One thousand kilocalories, or 1 million calories.

meiotic cycle--Also called meiosis. The division of egg and sperm cells. This cycle produces the gametes or sex cells. The steps in the cycle are prometaphase, metaphase, anaphase, and interphase.

Merychippus--An early ancestor of the modern horse.

mesentery--Where the small intestine lies in folds and coils near the left flank, being suspended from the region of the loin by an extensive fan-shaped membrane.

Mesohippus--An early ancestor of the modern horse.

messenger ribonucleic acid (mRNA)--The proteincoding instructions from the genes are transmitted indirectly through mRNA.

metabolic--Pertaining to the normal biochemical processes of the body.

metabolic alkalosis--Condition in the body when the pH increases to above the normal levels.

metabolic disorder--Any abnormalities in normal body functions.

metabolism--The physical and chemical processes in an organism by which living matter is produced, maintained, and destroyed, and by means of which energy is made available.

metabolites--The products of metabolism.

metabolizable energy (ME)--Energy in the feed that is useful to the animal for growth, production, and reproduction. It is the portion of the gross energy that is not lost in the feces, urine, and gas.

metritis--Inflammation of the uterus.

microbial action--Digestion by very minute organisms.

microchip--A small silicon chip the size of a grain of rice; contains the horse's registration number or identification number. A specially designed needle and syringe are used to implant the microchip.

microfilaments--Long, thin, contractile rods that appear to be responsible for the movement of cells, both external and internal.

microminerals--Minerals found in the body in small quantities, for example, iron and zinc.

microsatellites--Composed of simple repeats of DNA subunits, primarily in chromosomal regions not used as templates for protein synthesis. These genes are chosen as effective for identifying individuals and verifying parentage, not for their value in making horse-breeding decisions.

microtubules--Hollow, cylindrical groupings of tubelike structures that help give the cell shape and form. They are also involved in other cell processes.

midges--Blood-sucking arthropods used as an intermediate host to the nematode onchocerciasis. This parasitic infection usually occurs in the connective tissue, flexor tendons, and suspensory ligaments of the horse.

milk teeth--The first teeth that an animal develops.

mimicry behavior--Imitating the behavior of another animal.

minerals--Essential nutrients for horses, for example, calcium and phosphorus.

miniature--A very small horse.

Miocene epoch--A division of geologic time beginning about 23 million years ago.

mites--Various small parasitic arachnids; closely related to ticks. They are a secondary host for tapeworms.

mitochondria--Cell structures composed of an outer membrane and a winding inner membrane. A series of chemical reactions that occur on the inner membrane convert the energy of oxidation into the chemical energy of ATP. Almost all of the energy passes through this molecule before being used in cell function.

mitosis--Cell division that occurs in plants. The steps in mitosis are early prophase, late prophase, metaphase, anaphase, telophase, and interphase.

molars--Permanent teeth.

Monday morning disease--Another term for azoturia.

monkey mouth--Where the lower jaw and tooth structure extend beyond the top teeth.

monodactyl--Having a single toe.

moon blindness--Periodic ophthalmia or moon blindness is an inflammation of the inner eye. It is due in part to a vitamin B deficiency. It usually impairs vision and treatment is usually unsuccessful.

morphogenesis--The process of development during which cells differentiate into specialized types of cells.

Morrill Land Grant Act--Federal law that established land grant institutions in each state.

mortality insurance--Insurance covering financial losses due to the death of a horse.

motile--Exhibiting or capable of movement.

motion behavior--Predictable behavior exhibited by an animal in normal movement.

mouth speculum--An instrument used to hold a horse's mouth open.

mucous membranes--A membrane that lines the cavities in the body and connects the inside of the cavity to the outside.

mucous secretions--Viscous, slippery secretions produced by mucous glands.

mule--A cross between a female horse and a male donkey.

muscle tone--Development of strength and firmness of muscles.

mustangs--Wild horses; native horses of the Western plain.

mutagen--An abnormal cell.

myelin--The substance that covers certain axons and nerve fibers.

myofibrils--Long, thin tissues that are the contractile elements within muscle cells.

myosin--A protein present in muscle tissue.

myxoviruses--A type of virus that attacks the entire respiratory track.


nasal--Pertaining to the nose.

National Research Council (NRC)--Examines literature and current practices in the nutrition and feeding of horses and publishes recommendations on horse nutrition.

navicular bone--A small bone located in the horse's foot.

navicular disease--Inflammation of the navicular bone. It causes horses to go lame.

neck--The joining of the root and gum.

necrosis--Death of tissues.

nematodes--Parasitic worms--called roundworms--with unsegmented, cylindrical bodies. They have complete digestive systems.

neonatal--Relating to or affecting the newborn shortly after birth.

nephrons--Part of the kidney; a renal tubule.

nerves--Bands of white tissue emanating from the central nervous system and ganglia and extending to all parts of the body.

net energy (NE)--The energy fraction of the feed remaining after fecal, urinary, gas, and heat losses are subtracted from the gross energy. Net energy more precisely measures the real value of feed.

net worth--Financial condition of a business listing all assets, values of assets, and liabilities of a business.

neurotransmitter--A biochemical used to transmit a nerve impulse at a synapse, for example, actecholine or epinephrine.

nippers--(1) First incisors; also called centrals. (2) In horseshoeing, a tool used to remove extra hoof wall.

nomenclature--A set or system of names.

nonadditive gene--The members of the gene pairs are not equally expressed when non-additive gene pairs control a trait.

noninfectious--Diseases caused by environmental problems, nutritional deficiencies, or genetic defects.

nonruminant--Monogastric, or without a functional rumen.

nonruminant herbivore--A single-stomached animal that eats primarily plant material.

nucleotides--Basic building blocks of DNA, each composed of one sugar, one phosphate, and a nitrogenous base.

nucleus--Each cell contains this structure, which directs the activity of the cell.

nutrients--Substances that provide nourishment for the body.

nutritional deficiencies--Deficiency of any necessary substance that provides nourishment for the body.


off side--Right side of the horse.

olfactory--Sense of smell.

Oligocene epoch--A division of geologic time beginning about 37 million years ago.

omnivores--Eating both plant or vegetable and animal food.

onagers--Relatives of the horse.

open mare--A mare that was either not bred or did not conceive in the previous season.

ophthalmia--Inflammation of the eyeball or conjunctiva. See moon blindness.

orbital--The eye socket.

organ--Any part of an animal that performs a specific function.

organelles--The inside parts of a cell such as the Golgi apparatus, nucleus, ribosomes, centrioles, microfilaments, microtubles, lysosomes, and storage particles.

organic--Chemical compounds of carbon combined with other chemical elements and generally manufactured in the life processes of plants and animals. Most organic compounds are a source of food for bacteria and are usually combustible.

osmotic pressure--The pressure needed to prevent water from flowing across a semipermeable membrane into a more concentrated solution from a less concentrated one.

osselets--Soft, warm swellings over the front and sometimes sides of

the fetlock joint.

ossify--Cartilage being made into bone.

osteochondrosis--A metabolic disease of cartilage resulting in bone and joint defects.

osteomalacia--A disease in which the bones become softer. Occurs in adult animals.

ovaries--Endocrine glands in the female that produce the egg (ovum) at ovulation.

over-at-the-knee--The same as calf-kneed or buck-kneed.

overo--Either dark or white in color, with no white crossing the back. The spotting is usually roan and extends downward from the back. The tail is usually of one color. Overo horses usually have bald faces, and glassy eyes are common.

overreach--The hitting of the forefoot with the hind foot.

oviducts--The tubes through which the ovum passes to the uterus.

ovulation--The release of egg from the mature follicle on the ovary.


oxidative phosphorylation--A series of chemical reactions occurring on the inner membrane that convert the energy of oxidation into the chemical energy of ATP. In this process the predominant energy transfer molecule is ATP.

oxidize--To combine with oxygen to release energy.


pace--A fast, two-beat gait in which the front and hind feet on the same side start and stop at the same time.

paddling--To throw the front feet outward as they are picked up.

paddock--A small fenced area.

palatability--Acceptability of taste.

palatable--Appealing to the palate or taste.

Paleocene epoch--A division of geologic time beginning about 65 million years ago.

palpate--To examine by touch.

parasites--Organisms that live in or on another organism of a different species for the purpose of obtaining food.

parotid--The largest saliva gland.

parrot mouth--A result of the upper and lower incisors not meeting because the lower jaw is too short.

partnership--A form of business organization with multiple owners.

parturition--The act of foaling or giving birth.

passive immunity--Acquired by the transfer of antibodies from another individual; for example, colostrum.

passive transfer--The process by which antibodies are passed from mare to foal.

pastern--That part of the horse's leg between the fetlock and the coronet.

pasture mating--Natural mating.

pasturing--Grazing horses on grass or other forage.

patella--The flat, moveable bone at the front of the stifle joint of a horse.


pedal osteitis--Caused by chronic inflammation to the coffin bone, usually of the front feet. Persistent pounding of the feet, chronic sole bruising, or laminitis are causes.

pedigree--A record of the ancestry of an animal.

Pegasus--A mythological flying horse.

penis--The stallion's reproductive organ that is used to deposit semen or sperm into a mare's vagina.

perennials--Plants that normally continue to grow for three or more seasons.

performance record--The record tracking the actual ability and production of an animal or its offspring.

pericardium--The sac that encloses the heart.

periople--A varnish-like coating that holds moisture in the hoof and protects the hoof wall.

periosteum--A dense connective tissue that covers the surface of each bone.

peristalsis--Successive waves of involuntary muscle contraction passing along the walls of the intestine or other hollow muscular structures that force the contents onward.

permanent pastures--Pastures on which horses graze all the time.

perpendicular--Being or set at right angles to a given line or plane.

phantom--An object used for a stallion to mount instead of a mare.

pharynx--A short, somewhat funnel-shaped muscular tube between the mouth and the esophagus that also serves as an air passage between the nasal cavities and the larynx.

phenotypes--The visual characteristics of an animal.

photoperiod--Refers to the number of hours of light in a day.

photorefractory--A time when an animal fails to respond to changes in light.

pig-eyed--Those horses with sunken eyes, seeing less in front and behind than others do.

pincers--Also called centrals. First incisor teeth.

pincher--A tool used to remove horseshoes.

pineal gland--The gland in horses and most other mammals that is responsible for melatonin synthesis.

pinworms--Parasites that cause intense itching around the anus, from the females laying eggs there; the horse then rubs its hindquarters, resulting in the hair being rubbed off over the tailhead.

pitch--Jumping action of a horse in its attempt to unseat its rider.

placenta--The organ that develops in the female during pregnancy, lining the uterus and holding the fetus and attached by the umbilical cord.

plantar cushion--The part of the foot that expands and contracts to absorb shock and pumps blood from the foot back toward the heart.

plantar ligament--The ligament that runs behind the rear cannon bone in a horse.

plasma--The fluid portion of blood, as distinguished from corpuscles. Plasma contains dissolved salts and proteins.

plasma membrane--A very thin membrane of lipid (fat) and protein separating the cell from the environment and from other cells. It controls the transport of molecules in and out of the cell.

plates--Referring to a type of horseshoe.

Pleistocene epoch--A division of geologic time beginning about 2 million years ago.

Pliocene epoch--A division of geologic time beginning about 5 million years ago.

Pliohippus--An early ancestor of the modern horse; the first true monodactyl.

plumb line--When a weight is placed on the end of a string to measure the perpendicularity of something, such as the straightness of the leg of a horse.

pointing--A stride in which extension is more pronounced than flexion. A horse guilty of a pointed stride breaks or folds its knees very slightly and is low-gaited in front. Also indicates the standing position a horse frequently takes when afflicted with navicular bone disease or injury to the foot or leg, standing on three legs and pointing with the fourth.

points--Black coloration from the knees and hocks down as in bays and browns. Sometimes includes tips of ears.

poll--Having to do with the head area of the horse.

poll evil--A fistula--lesion or sore--on the poll; it is difficult to heal and caused by injury. This is an acquired unsoundness resulting from a bruise or persistent irritation in the region of the poll.

polyestrous--Having many heat cycles during the year. Mares have more regular cycles at the peak of breeding season when there is more light and no cycles at all during the winter months.

polyvinylchloride (PVC)--A type of plastic used in building materials.

pommel--Upper front part of a saddle; a saddlebow.

pony--A breed of very small horse that is not over 14 hands high.

posterior--Backward (in space).

postpartum--The time immediately after birth.

poultice--A moist, mealy mass applied hot to a sore or inflamed part of the body.

pounding--Heavy contact with the ground, usually accompanying a high, laboring stride. Faults in conformation that shift the horse's center of gravity forward tend to create pounding.

precipitates--To separate out from a solution.

premaxilla--The area of the jaw that contains cavities for the six upper incisor teeth.

premolar--Temporary teeth.


principal--Property or capital.

profitability--Money remaining after all fixed and variable costs are deducted from net income.

progeny--Offspring or descendants of one or both parents.

progesterone--A hormone that is released by the ovary before the fertilized egg is implanted.

proglottids--The segments of a worm.

prolactin--A hormone involved in lactation produced by the anterior pituitary.

proprioceptors--The joint proprioceptors give the horse a sense of the positions of its limbs. A sensory receptor situated within the body that is responsive to internal stimuli.

prostaglandins--A group of hormones that are unsaturated fatty acids and responsible for control of the estrous cycle and timing of parturition.

protozoal--Any of a subkingdom or phylum of animals containing microscopic, single-celled organisms that reproduce typically by binary fission.

protozoans--Single-celled animals that occur in the bloodstream and intestinal tract of horses.

proud flesh--Excess scar tissue on an injured area.

proximal--Situated closer to the origin.

Przewalski's horse--The oldest species of horse still in existence. This horse was only discovered in the late nineteenth century.

puberty--Sexual maturity; the age when an animal becomes capable of reproduction.

puff--See road puffs.

puller--Tool used to remove worn horseshoes.

pulse--Expansion and contraction of the arteries.

pupae (pl.), pupa (sing.)--Stage of insect development between larvae and adult during which the insect is quiescent.


qualitative traits--Traits usually controlled by a few genes showing sharp distinction between phenotypes, for example, coat color.

quantitative traits--Traits controlled by many pairs of genes with no sharp distinction between phenotypes, for example, growth rate and speed.

quick-release knot--A knot that unties quickly or breaks loose for the safety of the animal or the handler.

quidding--A condition in which horses drop food from the mouth while in the process of chewing. It is usually caused by bad teeth or bad gums (stomatitis or gingivitis). It can also be caused by paralysis of the tongue.

quittor--A festering of the foot anywhere along the border of the coronet. It may result from a calk wound, neglected corn, gravel, or nail puncture.


rack (single foot)--A fast, flashy, unnatural, four-beat gait in which each foot meets the ground separately at equal intervals; originally known as the "single-foot," a designation now largely discarded.

radius--The shorter and thicker of the two bones of the forearm.

random segregation--The random transfer of chromosomes and their genes to form gametes.

rasp--A tool used for leveling the horse's foot.

rate of passage--The time required for something to move through an area.

ration--The feed allowed an animal during a 24-hour period.

reactive behavior--Activities horses use to maintain themselves in harmony with their environment and adjust to sudden, potentially harmful changes.

receptors--The part of the neuron that receives internal and external stimuli such as sight, taste, smell, or hearing.

recessive allele--A gene that is not expressed.

rectum--The terminal part of the intestine.

red blood cells--Originate in the red bone marrow, liver, and spleen, and carry oxygen from the lungs to the tissues.

reflexes--Signals traveling on the afferent nerves that never reach the brain. They go directly to the spinal cord and then back to the efferent nerves and the muscles. An example would be a kick in response to a surprise.

registered--A horse whose name, along with the name and number of its sire and dam, has been recorded in the records of its breed association.

relaxation--Controlled by the nervous impulses received by the muscle cells, a muscle either contracts or relaxes.

relaxin--A hormone from the ovaries that causes relaxation of the pelvic ligaments and possibly relaxation of the cervix at parturition.

respiration rate--The number of times an organism breathes in a minute.

resume--Summary of an individual's employment and educational history.

reward training--Positive reinforcement.

RFID--Stands for radio frequency identification; an automatic identification method relying on storing and remotely retrieving identifying data about a horse, animal, or product; devices called chips, tags, or transponders are attached to or incorporated into a product, animal, or person for the purpose of identification using transmitted radio waves; tags or chips can be active (power source required) or passive.

ribonucleic acid (RNA)--A substance found in the cytoplasm and nuclei of cells that promotes the synthesis of cell proteins.

ribosomes--Tiny particles within the cell made of RNA and protein; present in large numbers in most cells. They are the site of protein synthesis.

rickets--A bone disease in young horses; caused by a deficiency of calcium.

ridgling--Also called a cryptorchid. A horse with one or both testes maintained in the body cavity; the horse is sterile if both testes are undescended, but fertile if one testis is suspended.

rigging--The part of the saddle involved in securing the cinch around the horse.

ringbone--A bony enlargement on the pastern bones, front or rear. It is caused by bony development around these joints due to tearing and damage of the ligaments and tendons at these bones.


risks--A chance of encountering harm or loss.

road puffs--Soft enlargements located at the ankle joints and due to enlargement of the synovial (lubricating) sacs; also called windgalls.

roadsters--Horses used for driving; includes heavy and fine harness horses and ponies.

roan--More or less uniform mixture of white with black hairs on the body, but usually darker on head and lower legs; can have a few red hairs in mixture.

roaring--The sound made when air is inhaled into the lungs; also called whistling.

rodeo--A public event in which the more exciting features of a roundup are presented, as the riding of broncos, branding, lariat throwing, etc.

rolling--Excessive side-to-side shoulder motion. Horses wide between the forelegs and lacking muscle development in that area tend to roll their shoulders. The toe-narrow fault in conformation can also cause rolling.

rotational grazing--The practice of changing the pasture areas of horses for better utilization.

roughage--Feedstuffs with a high fiber content.

roundworms--Nematode worms having no segments.

run--See gallop.

run up--The process of sliding an English stirrup iron up the inside of the stirrup leather so that it does not bounce on the horse's side or get caught on a projection.

running martingale--A strap that terminates with two rings, that when properly adjusted, has the effect of preventing the elevation of the head beyond a certain level.

running walk--A slow, four-beat gait, intermediate in speed between the walk and rack. The hind foot oversteps the front foot from a few to as many as 18 inches, giving the motion a smooth gliding effect. It is characterized by a bobbing or nodding of the head, a flopping of the ears and a snapping of the teeth in rhythm with the movement of the legs.

R value--The level of insulating ability of a material. The higher the number the better the insulative factor.


saliva--Fluid that moistens and lubricates the mass of food for swallowing and, as a digestive juice, acts on the starches and sugars.

sarcolemma--The outer envelope of skeletal muscles.

scalping--Occurs when the hind foot hits above or at the line of the hair (coronet) against the toe of a breaking-over (beginning the next stride) forefoot.

scapula--The shoulder blade.

scars--Marks left on the skin after the healing of a wound or sore. They may appear on any part of the body.

scratches (grease heel)--A low-grade infection or scab in the skin follicles around the fetlock.

scrotum--The pouch containing the testicles.

secretory--Products produced by glands in the body that aid in digestion.

selenium--A mineral required in the diet.

semen--Sperm cells plus fluid from the accessory glands.

seminiferous tubules--Small coiled tubules in the testes where spermatozoa are produced.


serviceability--The usefulness of a horse for its intended function.

sesamoid bones--The two pyramid-like bones that form a part of the fetlock or ankle joints on the front and rear legs of a horse.

sesamoiditis--A condition that consists of a fracture of one or both of the pyramid-like bones that form a part of the fetlock or ankle joints and join with the posterior part of the lower end of the cannon bone.

settle--Breeding successfully.

settling percentage--The percent of mares bred that conceive.

sex determination--Where females carry the XX chromosome and the males carry the XY chromosome.

shareholders--Owners of a share of a company; stockholders.

sheath--The double fold of skin that covers the free portion of a male horse's penis.

shock--A state of profound depression of the vital processes of the body.

shod--Refers to a horse with horseshoes.

shoe boil--Also called capped elbow. A soft, flabby swelling at the point of the elbow; it is usually caused by contact with the shoe when the horse is lying down.

shoe boil roll--Same as a boot.

shoeing apron--A piece of heavy clothing used to protect the horseshoer.

short cycle--A cycle that runs shorter than a normal estrous cycle.

sidebones--When the lateral cartilages ossify making the horse hard-at-the-heels.

silage--Fermented roughage.

silent heat--An estrous period with no outward signs of receptivity to the male.

singeing lamp--An apparatus used to burn the long hairs off a horse's body.

sire--The male parent of a horse.

small colon--Part of the large intestine where the moisture in the food is reabsorbed.

small intestine--The site of most nutrient absorption.

smooth mouth--Refers to a horse that has no cups present in the permanent teeth.

snaffle bit--A bit that works with direct action on a horse's mouth. A snaffle bit may have a jointed or a solid mouthpiece.

snip--A white or beige mark over the muzzle between the nostrils.

soft skills--Cluster of personality traits, social graces, facility with language, personal habits, friendliness, and optimism possessed by individual to varying degrees; for example, work ethics, teamwork, courtesy, self-discipline, self-confidence, and language proficiency.

soil test--Used to determine contents of soil and whether fertilizer or some other substance is needed to increase yield.

sole--The bottom of the hoof.

sole proprietorship--Form of business organization where one individual owns the business.

solvency--Having sufficient means to pay all debts.

space requirements--Refers to the area needed for the size, type of operation, and number of animals in a building.

speedy-cutting--Occurs when a trotter or pacer traveling at speed hits the hind leg above the scalping mark and against the shoe of a breaking-over forefoot.

spermatozoa--Male reproductive cells.

spinal cord--One of the most important parts of the central nervous system. This system supplies the body with information about its internal and external environment. It conveys sensation impulses to the brain or spinal cord and other parts of the body.

splint--An inflammation of the interosseous ligament that holds the splint bones to the cannon bone causing swelling. Usually associated with conformation problems.

splint boots--Protective covering for the front legs, extend from below the knee to just above the fetlock.

spooky--A horse that is easily frightened.

sprain--Any injury to a ligament usually occurring when a joint is carried through an abnormal range of motion.

spring--The manner in which weight settles back on the supporting leg at the end of the stride.

sprung--The appearance of the ribs when the mare develops a wider stride to compensate for the increased weight she is carrying during pregnancy.

stall--A compartment or cubicle for horses.

stall walking--When a horse walks too much in its stall. It reduces condition and induces fatigue.

stallion--A male horse over 4 years of age.

stamina--Ability to endure.

star--A solid white mark on the forehead. The shape may range from oval to diamond to a narrow vertical, diagonal, or horizontal star.

stay apparatus--Consists of ligaments and tendons that stabilize all the joints of the forelimb and the lower joints (the fetlock and pastern) of the hind limb so minimal muscular activity is needed to hold tension on these ligaments and tendons, which in turn prevent flexing of the joints and collapsing of the leg; allows the horse to balance its weight on its legs almost like legs of a chair.

step--The distance between imprints of the two front legs or the two back legs.

steppes--Vast semiarid, grass-covered plains, as found in southeast Europe, Siberia, and central North America.

stepping pace--Also known as slow pace. A modified pace in which the objectionable side or rolling motion of the true pace is eliminated because the two feet on each side do not move exactly together. Instead, it is a four-beat gait with each of the four feet striking the ground separately.

sterile--Free from living microorganisms; unable to reproduce.


steroids--Fat-soluble organic compounds. These inactivated hormonal substances are water soluble and are readily eliminated through the urine.

stifled--Refers to a displaced patella of the stifle joint sometimes crippling the horse permanently.

stillbirth--When a foal is born dead.

stimuli--Any factors or environmental changes producing activity or response.

stock--Livestock domesticated for farm use.

stocking--A white marking from the coronet to the knee.

stocking plus--A white marking like the stocking, but the white extends onto the knee or hock.

stocking rate--Number of animals per acre of pasture.

stomach hairworm--A tiny nematode parasite, very thin and hair-like.

stomach worm--A parasite that produces fibrous tumors or numerous nodules that, if close together, form a tumor. They cause gastric and cutaneous habronemiasis. Source of summer sores.

stomatitis--Inflammation of the mouth.

straight shoulders--A conformation problem that will give a horse a hard gait and possibly cause trouble keeping a saddle in place.

strategic planning--Analyzing the business and the environment in which it operates to create a broad plan for the future.

stress--A demand for adaptation. There are four categories of stress--behavioral, immunological, metabolic, and mechanical.

stride--The distance between successive imprints of the same foot.

stride stance--The weight-bearing phase of the stride.

stride suspension--The non-weight-bearing phase of the stride.

stringhalt (stringiness, crampiness)--An ill-defined disease of the nervous system characterized by sudden lifting or jerking upward of one or both of the hind legs; most obvious when the horse takes the first step or two.

strip--Also called stripe. A white mark starting at eye level or below and ending on or above the upper lip. The size and shape of a stripe may vary widely and must be described in detail as to width, length, and relationship (whether it is connected or unconnected) to a star.

stripe--See strip.

strongyles--Part of the large groups of parasites known as roundworms.

stud books--Permanent books of breeding records.

summer sores--Parasitic infections caused by stomach worms where lesions ooze serum, are very itchy, and disappear in cold weather. They occur where horses cannot reach them.

supplement--A feed or mixture richer in a specific nutrient than the basic feedstuffs in a ration.

sweeney--A wasting away of the shoulder muscle overlying the scapula of the horse.

swing--The non-weight-bearing phase of the stride.

synapses--The connections between nerve cells.

synovitis--Inflammation of a synovial membrane.

systemic--Affecting the whole.


tack--Equipment used in riding and driving horses, such as saddles, bridles, etc.

tail board--Used in the prevention of tail rubbing.

tail rubbing--Constant rubbing of the tail from irritation of parasites. Sometimes develops into a habit.

tandem--A type of trailer in which the horses ride side by side.

tapeworms--Large worms that have a head and proglottids or segmented bodies that attach to the intestine of the horse.

tattoo--An identifying mark, on the mucous membrane on the upper lip, made by rubbing ink into perforations made by a tattoo gun.

temporary pastures--Pastures on which horses graze part of the time.

tendon--Part of the bands of tough, fibrous connective tissue forming the end of a muscle that serves to transmit its force to another part.

territorialism--Gives the horse space for its basic functions and for care of its home and feeding.

testes--The male reproductive organs producing sperm cells and hormones.

tetanus shot--An injection that helps protect an animal from developing the disease tetanus (lockjaw).

thoracic--Of or pertaining to the thorax (the area between the neck and the abdomen).

thoroughpins--A distention of the synovial bursa, and considered a discrimination. They can be pressed from side to side.

threadworm--An intestinal parasitic worm that is unique because only the adult female is parasite, it can exist outside the host; also contributes to foal heat diarrhea.

throatlatch--The part of the bridle under the horse's throat that connects the bridle to the head.

thrombin--A biochemical in the blood partially responsible for the process of clotting.

thrush--An inflammation of the fleshy frog of the foot caused by a fungus. It is blackish in color, foul smelling, and associated with filthy stalls. It may cause lameness.

thyroid--The gland that secretes thyroxin, the hormone that controls the rate of metabolism.

ticks--Blood-sucking parasites; often an intermediate host; can cause death in foals.

tie down--A strap that, when properly adjusted, has the effect of preventing the elevation of the head beyond a certain level without cramping the horse.

tie stall--A stall in which a horse is fastened by a halter.

tissue--The structured groupings of cells specialized to perform a common function necessary to the survival of the horse.

titer--The strength of a solution as determined by titration.

tobiano--A white horse in which regular, distinct spots extend down over the neck and chest. All four legs are white, and the face is usually marked the same as in other color patterns found in horses.

total digestible nutrients (TDN)--Indicates the energy density of a feedstuff. TDN takes into account the amount of fat, protein, and carbohydrate in the feed.


trace--mineralized salt--Salt containing a mixture of the microminerals.

trailer sour--Horses that become fearful of trailers and are difficult to haul.

trappy--A gait that is a short, quick, choppy stride. Horses with short and steep pasterns and straight shoulders tend to have a trappy gait.

trauma--An injury or wound to a living body.

traverse or side step--The traverse or side step is a lateral movement of the animal to the right or left as desired without moving forward or backward.

tree--Basic unit of a saddle; the tree determines the shape of the saddle and may be made of plastic, fiberglass, aluminum, or wood covered with rawhide.

Triple Crown winners--Three-year-old horses winning all three of these races in one season: Kentucky Derby at Churchill Downs, Preakness at Pimlico in Baltimore, and Belmont Stakes at Elmont, New York.

Trojan Horse--A classic legendary horse in which Greek soldiers hid to gain entry into the ancient city of Troy.

troponin--A special protein involved in muscular contraction.

trot--A natural, rapid, two-beat, diagonal gait in which the front foot and the opposite hind foot take off at the same split second and strike the ground at the same time.

turbinates--Soft, bony structures in the head. These structures are supplied with a great deal of blood.


tying-up syndrome--A metabolic disorder of the muscles that is associated with forced exercise after a period of rest during which the animal has access to feed; thought to be a mild form of azoturia.


ulcerate--To break skin or mucous membranes.

umbilicus--The navel.

unconditioned response--A response that occurs without practice.

unicorn--A mythological horselike animal that had a single large horn in the middle of its forehead.

unnerve--Cutting or removing a nerve from the body.

unsoundness--Any condition that interferes or is apt to interfere with the function and performance of the horse.

unthriftiness--Unhealthy or inefficient condition; lacking vigor or bloom.

upright pasterns--straight, vertical pastern bone--a conformation problem.

ureters--Part of the urinary system that passes urine to the bladder.

urethra--The canal through which urine in the female and urine and semen in the male are discharged.

urine--The fluid that contains nitrogenous waste and any excess salts or sugars not required by the body.

uterus--Part of the female reproductive tract; it consists of a body, cervix, and two horns, one of which receives the fertilized ovum for development.


vaccine--A substance that is either inactivated killed organisms or modified live organisms prepared for inoculation. It stimulates the immune response and/ or produces durable immunity with a single dose.

vacuoles--Large liquid-filled areas in cells.

vagina--The part of the female reproductive tract that receives the sperm during mating and functions as a passageway during parturition.

variable costs--Costs that increase or decrease in relation to an increase or decrease in production.

veins--Vessels that carry blood from the tissues to the heart.

venae cavae--The large veins entering the heart.

ventilation--Air movement in and out of a building.

ventral--Surface opposite the backbone.

vertebrae--Any of the bones or segments in the spinal column.

vertebral column--The backbone.

vesicle--A small, thin-walled cavity.

veterinarian--An animal doctor.

vices--Habits acquired by some horses that are subjected to long periods of idleness. Hard work and freedom from close confinement are distinct preventives.

viral--Of, pertaining to, caused by, or the nature of a virus.

visceral--Smooth muscle is sometimes called visceral muscle.

vital signs--Indications of an animal's health: heart rate, temperature, and respiration rate.


walk--A natural, slow, flat-footed, four-beat gait; each foot takes off from and strikes the ground at a separate interval.

warmblood--Refers to the overall temperament of light to medium horse breeds. Warmblood horses are fine boned and suitable for riding.

water-soluble vitamins--Vitamins that are available in feedstuffs or synthesized by microorganisms in the intestine.

waxed teats--When drops of sticky, clear, or amber-colored fluid excreted prior to parturition become dried and hard, coating the ends of the teats and giving them a waxy appearance.

way of going--How a horse moves.

weanling--A foal that has been weaned from its mother.

weaving--A rhythmical shifting of the weight from one front foot to the other. It is not a common vice, but when carried to extremes, it renders a horse almost useless.

wet mare--A mare that has foaled during the current breeding season and is nursing the foal.

whistling--A paralysis or partial paralysis of the nerves that control the muscles of the vocal cords; also called roaring.

white blood cells--The active agents in combating disease germs in the body.

white on knee or hock--A separate white mark on the knee or hock.

white spots--White spots on the front of the coronet band or on the heel.

wind puffs--Soft enlargements located at the ankle joints and due to the enlargement of the synovial (lubricating) sacs.

windgalls--Soft enlargements located at the ankle joints due to enlargement of the synovial (lubricating) sacs. Also called road puffs.

winding--Twisting the front leg around in front of the supporting leg as each stride is taken. Sometimes it is called threading, plaiting, or rope-walking. Wide-chested horses tend to walk in this manner. Winding increases the likelihood of interference and stumbling.

wind-sucking--When a horse identifies an object on which it can press its upper front teeth while pulling backward and sucking air into the stomach, usually accompanied by a prolonged grunting sound. The habit is practiced while eating, thus causing loss of food.

winging outward--An outward deviation in the direction of the stride of the foreleg. It is the result of a narrow or pigeon-toed standing position. Winging is exaggerated paddling and very noticeable in high-stepping horses.

winking--When the mare raises her tail to urinate, and the labia open to expose the clitoris, while she assumes a mating position.

withers--The highest part of the back located at the base of the neck in a horse.

wolf teeth--The first permanent premolars.

wound--A disruption in the integrity of living tissue, caused by physical means.

wry muzzle--A distortion of the muzzle.


yearlings--Horses between 1 and 2 years of age.


zygote--Cell formed by the union of the male and female gametes (the sperm and egg) and the individual developing from this cell.
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Author:Parker, Rick
Publication:Equine Science, 3rd ed.
Article Type:Glossary
Date:Jan 1, 2008
Previous Article:Appendix.

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