Chapter 14: Avian.
After completing this chapter, the student should be able to
* properly house a companion bird with the appropriate cage size, perches, and toys.
* provide appropriate client education to new bird owners.
* provide a proper diet for the different species of companion birds.
* provide basic nursing and emergency care to a bird.
* provide nutritional support to an ill bird through tube feeding.
* assist in the anesthesia of a bird.
* demonstrate appropriate restraint techniques.
Aviculture, the keeping of companion birds, has been a part of human culture for centuries. Birds were kept for their songs, beautiful colors, intelligence, and, of course, the wonder of flight. The feathers of exotic birds have been used to decorate ceremonial dress, birds of prey were trained as hunting companions in the ancient art of falconry, pigeons were employed during war time to deliver messages behind enemy lines, and then there was the wonder of speech. Today, birds are kept for all these reasons and more. They are the third most popular companion species, following only after dogs and cats (Figure 14-1).
There is such great variety in the types of companion birds, from the smallest singing finches to the largest macaws, that there can be no one volume that could even begin to cover or keep up with current information.
In general, companion birds are limited to a few taxonomic families: those commonly and collectively called parrots, finches, soft-bills, pigeons, and doves. Within each of these groups is an enormous variety of species, each with their own distinct characteristics, behaviors, and personalities. Diet and husbandry requirements that meet their needs are just as specific.
Birds are classified according to their anatomical features. Psittacines are those birds with powerful hooked beaks. They have four toes, two forward and two back. In addition to perching, they use their feet to pick up and hold food items, to play, and to climb. This group is collectively called parrots or hookbills. Popular species include budgerigars, cockatiels, cockatoos, conures, amazons, macaws, and the African parrots. Psittacines are known for their ability to talk, their intelligence, and their longevity. Some hookbills may live 60 years or more.
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Passerines are the largest group and include the song birds. They have small straight beaks and four toes; three toes are directed forward and one back. Passerines do not use their feet like psittacines and are often called perching birds (Figure 14-2). They are usually too small to become hand tame but are enjoyed for their variety of songs and color. Included in this group are an enormous variety of finches and canaries. They have a much shorter lifespan of four to eight years.
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Many of the finches are also softbills to distinguish them from the seedeaters. Softbills require different diets and generally do not eat seeds, but feed mainly on insects and a variety of fruits.
A separate group, Rhamphastidae, includes toucans, toucanettes, and aricaris. These are often kept in display aviaries rather than as companion birds. They have very specific dietary requirements and are not usually hand-tamed. They eat a variety of fruits, insects, small mammals, and lizards. They are kept for their beauty and relative rareness. This group has very large beaks for catching prey, which they toss into the air and swallow whole.
Pigeons and doves are very popular and are usually housed outdoors in lofts. They are known for their homing instincts and gentle nature. Flocks of homers may often be seen in the sky as they fly back to the loft, returning after morning exercise.
A HOMING PIGEON is a domesticated rock pigeon that has been selectively bred to be able to find its way home over long distances. Some of the longest flights recorded have been greater than 1600 miles. Many of these birds compete in races. Pigeon racing is a popular sport the world over.
There are many varieties of fancy pigeons. They are not only raced, but are exhibited in specialty shows, released at functions, and enjoyed by millions who just enjoy watching their flocks whirl and swoop though the air.
Pigeons and doves are Columbiformes. Pigeons are larger with squared tails. Doves are much smaller with tail feathers that end in a point. They are unique in that both parents produce crop milk to feed their young, known as squabs.
Respiration in birds is quite different from that of other species. The lungs are fairly rigid and lay flat against the dorsal vertebrae and ribs. Most birds have eight air sacs that assist with respiration. Movement of the breast muscles, keel bone, and ribs provides for lung respiration and also inflates the air sacs. Inspired air moves from the lungs and through the air sacs before returning to the lungs and exhaling exchanged gases. Birds do not have a diaphragm to assist in respiration (Figure 14-3).
Avian digestion also differs compared to other species. Food enters the oral cavity and travels down the esophagus to the crop. The crop is an expandable food storage pouch (Figure 14-4). After leaving the crop food passes to the proventriculus, or true stomach. The proventriculus contains digestive enzymes that start to break down the food. From the proventriculus, partially digested food travels to the ventriculus, commonly called the gizzard. The strong, tough muscles of the ventriculus grind the food before it enters the small intestine, where nutrients are absorbed. Waste products are expelled from the cloaca. The cloaca is not only the terminal collecting sac for the digestive system, but the urinary tract also empties into the cloaca before waste is expelled. The cloaca is a major organ of the reproductive tract where sperm is deposited and eggs are delivered (Figure 14-5).
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Males have two testicles enclosed within the abdominal cavity (Figure 14-6). During breeding season, the testicles enlarge as they produce sperm. In many birds, only the left testicle is functional. Females, while having two ovaries, usually have only one that is functional and this, too, is on the left side (Figure 14-7).
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With some species, sex determination is easy and can be done visually. Birds with distinctly different physical appearances between males and females are called sexually dimorphic. For example, the cere of a male budgerigar is blue and the female has a tan or pale pink cere. The Eclectus parrot has an even greater difference: males are bright green and females are red. In some species, sound may be identifying; for example, only the male canary sings. In other species, it is not possible to determine sex visually. Positive identification is usually determined through DNA testing. A single feather sent to a lab is all that is required. Previously, before DNA testing, birds were examined surgically. The procedure required the bird to be anesthetized and the reproductive organs examined internally. This put the bird at risk and is not now usually performed in companion birds.
Some species have an uropygial gland located at the base of the tail. The gland produces oils that the bird uses when preening. Birds rub their beaks over the gland, picking up the oils, which are transferred and groomed into the feathers. All birds preen to clean and maintain their feathers.
Birds have six different types of feathers. Contour feathers are found on the wings and tail; they cover the body and outline its shape. The wing feathers are rectrices and the tail feathers are remiges (Figure 14-8).
Down feathers are close to the body and provide warmth. Down feathers are the first to appear in newly hatched chicks. Semiplumes lay under the contour feathers and over the down feathers. These also help insulate and keep the bird warm. Some down feathers produce a fine white powder that provides waterproofing. These feathers are called powder down feathers to distinguish them from those which only provide warmth. Some species such as cockatoos and African Greys produce a greater amount of feather dust than other birds. Filoplumes are small, hair-like feathers with barbs along the shaft that help guide the bird in flight and reposition the feathers. Bristle feathers are on the head, around the eyes and nares. These are sensory feathers (Figure 14-9).
New and growing feathers have a rich blood supply that nourishes the feather as it grows. As the feather matures, the blood supply recedes and the shaft of the feather becomes clear. If a large growing contour or flight feather is broken or damaged, it will bleed profusely. To stop the bleeding, the broken blood feather needs to be completely removed. It should be grasped firmly with forceps, close to the skin, and pulled directly out in the same direction as the feather growth. The blood vessel will seal off under the skin. Direct pressure on a blood feather will usually not stop the bleeding. Traumatized birds have been known to bleed to death from broken blood feathers. Extraction of a blood feather is painful and anesthesia is required, especially in large birds.
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Molting, the natural replacement of feathers, occurs in birds once or twice a year. This can be influenced by season, health, and nutrition. Most molts take several weeks to complete. Molting can be a stressful time for a bird. Birds that are normally vocal often become subdued and quiet. Care should be taken with molting birds, as blood feathers are coming in and they can potentially be more vulnerable to damage.
Flock status is very important in establishing hierarchy and social order. When people acquire companion birds, they become part of the social order. In the wild, the birds on the highest branches are the dominant birds. With companion birds, the flock status is no different. The higher the bird is placed, either by cage location or while socializing with a human, determines rank and social status. Many behavioral issues with birds are a direct result of placing the bird above the owner's head or allowing the bird to sit on a shoulder, giving the bird priority at the top of the perceived hierarchy.
Birds are very intelligent. They have the ability to use tools, problem-solve, and transfer learned information. Because of this level of intelligence, they require daily interaction with humans or other birds. They need to be provided with toys appropriate for their mental abilities, toys that interact, stimulate, and entertain. Many behavioral problems seen in birds are created by boredom. Some birds become aggressive, cage territorial, and bite. Others begin to feather-pick out of boredom and from little or no social interaction with people (Figure 14-10). Birds that are hand-raised by humans imprint and bond with people, not other birds, and need daily quality time from their human flock.
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Species that speak also use appropriate vocabulary for their situation. African Greys in particular are very vocal about their predicament and will complain clearly: Stop it! Don't do it!, Bad dog! Birds are cognizant and know exactly what they are saying and use the vocabulary they have to make their feelings very clear.
FOR MANY YEARS, Dr. Irene Pepperberg has studied the learning ability of parrots. Through her studies and others, we know that parrots are cognizant, intelligent, and have a greater ability of communication than once thought.
All birds need to be provided with as large a cage as possible. A cage is not just a place to contain a bird, but it becomes a safe place, a play ground, the source of food and water, and a sleeping area. Cages should be wider than they are tall. Birds do not fly straight up and down. Their flight and movements are more lateral or at a gradual incline. Round cages provide no place for a bird to settle into and feel safe.
Cages should not be coated with lead-based paint or made of galvanized metal. Cage bar spacing needs to be of the appropriate size for the bird so it cannot squeeze through the bars or become stuck between them.
Perches in the cages should vary in dimension with sizes appropriate for grasping and resting the feet. Natural wood, such as manzanita, makes ideal perches. They are available in varying widths and shapes and attach easily to cage bars. Manzanita wood is easy to clean and disinfect. Dowel rods and sand-covered perches should not be used. The constant abrasion from standing on sandpaper-covered perches creates sores on the bottoms of the feet. The foot wraps 3/4 of the way around a correctly fitted perch, and the nails do not come into contact with the surface of the perch, so the use of sandpaper covered perches is not a method of keeping nails trimmed. Perches should not be placed directly over food and water bowls where they can become contaminated with fecal material. Most birds have a sleeping perch, used only at night or when resting. It should be placed towards the back of a cage. Some birds, especially conures, use a sleeping tent that hangs from the cage top.
There are a variety of materials available for bird cage floors. The easiest, cheapest, and healthiest is still plain newspaper. Sawdust and wood shavings create dust that can cause respiratory problems and possible crop blockages if ingested. Ground corncob, walnut shells (which are toxic), and recycled paper products promote mold growth when they become wet. Birds pick up and play with many items, including cage substrates. They enjoy shredding newspaper but rarely swallow pieces.
The cage should be located in an area of the house where the bird is able to interact with family members, but not near the kitchen. Nonstick cookware, when heated, releases fumes that are toxic to birds. Burning food, such as micro-waved popcorn, can also release enough toxic fumes to kill a bird. Common household items that are toxic to birds include fumes from self-cleaning ovens, aerosol sprays, concentrated cleaning products, and oil-based paint. New carpet often contains formaldehyde, some candles contain lead, and scented air fresheners have also been implicated. These products can potentially cause respiratory distress and possibly death.
Placing the cage near a window is not recommended. Birds are easily frightened by things they see outside and panic. Dramatic temperature changes, magnified by the glass, can overheat the bird, or drafts from winter weather can chill the bird. Companion birds are most comfortable at room temperatures.
Not all birds eat seeds and birds that do should not eat them exclusively. Feeding a seed-only diet contributes to malnutrition and shorter life spans. Seed mixtures should be available free choice and be suitable for the species. Smaller species feed on a variety of plant seeds, including millet, rape, and linseed while mixes for larger birds contain safflower, sunflower, pumpkin, and cereal grains. Peppers, shredded coconut, and whole nuts are often found in the higher quality mixes.
Diets high in sunflower seeds can cause obesity. With the advances in understanding the nutritional needs of companion birds, formulated, pelleted diets have been developed. Pellets can be mixed in with seeds to allow the bird to become familiar with the new food. Neither seeds nor pellets exclusively will meet all the bird's needs.
Food also becomes enrichment and a part of family life in the human flock. Birds frequently share small portions of the family dinner. For the most part, it is safe to feed birds people food. Food items which should never be offered are avocados, onions, rhubarb, garlic, and some uncooked squashes which contain enzymes that can be toxic. Chocolate and caffeine are both on the NO list, as well as highly salted items, alcoholic beverages, and all food taken from the human mouth.
ASIDE FROM THE POSSIBILITY OF ZOONOTIC DISEASE TRANSMISSION, feeding a bird from the human mouth may send the wrong message to the bird. As birds bond with owners, they can also view them as mates. As a part of bird courtship behaviors, they regurgitate food to feed their chosen mate.
A wide variety of fresh fruits and vegetables should also be a part of the bird's daily diet. Other foods that can be added to the diet are cooked pasta, potatoes and rice, legumes that have been soaked and then cooked, cooked scrambled eggs, and hard-boiled eggs. Smaller birds, cockatiels, finches, and canaries seem to prefer vegetables over fruit. It can be difficult to tempt birds to try different foods if they were not introduced to them when they were chicks. The sense of smell is not very well developed in birds, but many companion birds have come to associate the sounds of certain noises in the kitchen with certain foods that they enjoy.
Lories and lorikeets require a specialized diet of nectar and do not eat seeds or vegetables. Powdered nectar is mixed with water and offered as a liquid. The tongue of a Lory has bristles that hold the nectar as it is lapped. They also eat very ripe and juicy fruit.
Pigeons and doves consume seeds whole. They eat a variety of cereal grains and pod seeds, such as peas and beans. Pigeons are fed different combinations of proteins and fats which better enable them to compete and race. Many pigeon breeders develop their own mixes of grain and legumes to enhance performance in racing or in specialty breeds, which are bred for show. Grit was often recommended for all companion birds. It was scattered on the cage floor or offered in a small dish. Grit was thought to be necessary for birds to digest seeds. Grit eventually ends up in the gizzard (ventriculus) where it grinds the food and breaks down the shell hull. Not all birds should have grit (bird gravel) and it can harm those that don't need it. It is now recommended only for birds, like pigeons and doves, that consume whole, intact seeds. Most other birds crack the seed hull and cast it aside before consuming the small kernel inside.
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Cuttlebones are recommended for small birds. Finches, canaries, cockatiels, and budgies all enjoy pecking on them. Cuttlebones provide a source of calcium and trace amounts of iodine. Nibbling on them also helps groom the beak. Cuttlebones are the endoskeleton of salt water cuttlefish, which are related to squid (Figure 14-11).
Restraint and Handling
Most companion birds are hand-tamed and willingly step up to an extended pair of fingers. Hookbills often use their beaks to grasp something prior to stepping onto it. This should not be taken as an attempt to bite. Jerking the hand away will earn immediate mistrust from the bird. It is the equivalent of offering someone a seat then pulling it out from under them. If a bird steps toward an extended hand, it is not likely that it will bite unless something frightens it or the person attempts to grab the bird.
By necessity, restraint for an exam or procedure requires a different approach from social interactions. Birds should never be restrained from the front. Even slight pressure on the keel bone and breast muscles will restrict respiration. Birds should always be retrained from the back, either cupped in the hand or wrapped in towel.
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The owner should be requested not to hand the bird to the restrainer, but allow the restrainer to safely catch up the bird. When an owner passes the bird, it can damage the trust the bird has with its human companion. The bird should be placed on a perch for the restrainer to retrieve and restrain (Figure 14-12).
The use of a towel as a restraint device prevents oils from the restrainer's hands from damaging the feathers and also acts as a distraction for the bird. Gloves should never be used with companion birds. They are frightening to the bird and can result in trauma to the patient. When wearing gloves, the restrainer is unable to feel the amount of pressure being applied to the bird. Birds should be approached from behind and the towel wrapped around them, including the wings. The patient should be grasped with one hand under the lower beak, avoiding pressure on the cheeks, which will result in bruising. (This is especially important with macaws that do not have feathers on their cheeks.) The other hand grasps both feet and supports the bird. To prevent regurgitation, the bird should be held upright. Holding the bird close to the restrainer offers security to the bird. Birds that arrive in their cages can also be retrieved with a towel. To avoid injury to the bird, toys, dishes, and perches should be removed prior to attempting to towel the bird inside the cage.
Most birds know exactly what the dreaded towel means and some will attempt avoidance at the very sight of it. If a bird panics with the approach of a towel, the lights should be turned off. Most diurnal birds are unable to see in the dark, and this will give the restrainer the advantage of retrieving the bird without difficulty. Toweled birds can become very vocal. Macaws scream loudly enough to cause ringing in human ears and many clinic staff have learned to be prepared and use ear plugs.
To restrain for venipuncture, the patient is wrapped in a towel and positioned on its left side. With one hand holding the head (thumb under lower beak and the rest of the hand around the back of the head) the other hand lowers the right wing down to expose the jugular vein.
Birds are susceptible to a variety of diseases. Some diseases are chronic while others are acute. There may be different forms of the same disease, with varying clinical signs. Many diseases and conditions result in death.
Bird droppings often indicate the health status of the patient. A normal dropping consists of three parts: fecal material is usually green or brown, urates are white, and the urine is clear and watery. Table 14-1 provides a summary of changes and conditions associated with bird droppings.
General signs of illness in birds include decreased appetite, discharge from the nares or oral cavity, decreased activity, abnormal droppings, and a huddled or fluffed appearance. Birds with respiratory disease often exhibit a tail bob. The tail feathers move up and down with each breath. They may also exhibit open-mouth breathing. Birds that are very ill may sit with their eyes closed (Figure 14-13).
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Bathing or showering at least weekly helps maintain feather health. Birds enjoy having a bath; they can be misted with a spray bottle, put into a sink with a sprayer, or taken into the shower. The water should be lukewarm and gently sprayed over the bird. Smaller birds will bathe in a small bowl of water placed on the cage floor.
All companion birds need routine nail trims and some birds may also require beak trims. In smaller birds, the nails can be clipped with tiny nail trimmers. In larger birds, nails can be trimmed with a dremel tool. The advantage to using a dremel is that it also cauterizes the nail if the quick is cut. Beaks can also be trimmed and shaped using the dremel (Figure 14-14). If a dremel is not used or bleeding from a cut nail or beak doesn't stop, a styptic powder is recommended. Silver nitrate sticks should not be used on a bird. While not toxic to dogs or cats, silver nitrate is toxic to birds if ingested. Correct trimming of nails and beaks requires knowledge of the tools used to avoid injury to the bird (Figure 14-15).
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Wing trims are often personal preference. Some owners prefer free flight or do not want their birds to appear to have incomplete wings. The purpose of trimming flight feathers is to prevent the bird from flying too far or too high. Most veterinarians recommend cutting the flight feathers (rectrices) just under the second row of contour feathers. The number to cut varies with different species. The feathers are cut from the distal end of the wing, trimming towards the body. Feathers should be examined from the underside of the wing and cut one at a time. Blood feathers should never be cut. If a blood feather is present, one mature feather on each side of the blood feather should be left to protect it. Scissors should not be used to cut straight across and through all of the feathers at once.
Leg bands placed on birds by breeders are for identification purposes. Breeder bands on young birds are fully closed. Quarantine bands placed by the USDA are open bands. Some owners like these to be removed so the bird will not get caught in the cage or on a toy. Leg bands are usually removed by a veterinarian using a pin cutter. Care has to be taken that the veins and arteries are not nicked in the process of removing the band from the leg. Bird bands are not proof of ownership as they can be quickly removed. One way to positively identify a bird and prove ownership is with a microchip implant. This is placed in the breast pectoral muscle.
Sour crop, or crop stasis, is not a disease but is usually a sign of other conditions. The cause may be a bacterial or a fungal infection. It also occurs in hand-reared chicks. Food that has been left out, reheated, or fed at the incorrect temperature is a common cause of sour crop. Not allowing the crop to completely empty before another feeding can also lead to crop stasis (Figure 14-16).
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Tumors may also invade the crop and become so invasive that they prevent the bird from storing food and filling the crop (Figure 14-17). Figure 14-4 shows a bird with a systemic tumor of the crop. The tumor took up three fourths of the crop capacity. Surgery was not an option due to the rich blood supply feeding the tumor.
A serious gastrointestinal disease of birds is proventricular dilatation disease, (PDD). This disease is thought to be caused by a virus that attacks the smooth muscle of the crop, proventriculus, ventriculus, and small intestine. PDD causes delayed motility in the gastrointestinal tract and dilatation of the organs. Common signs include weight loss, regurgitation, crop impaction, and eventual death.
Beak deformities can be either congenital or acquired. The most common cause is trauma. In young birds, trauma-related injuries are due to aggression among cage mates and aggressive feeding of chicks by parent birds. Scissor beak is a common congenital deformity where the upper beak is bent to one side.
Psittacine beak and feather disease (PBFD) is caused by a virus that can be transferred from an infected hen to the egg or directly to feeding chicks. It is also transmitted by inhalation or ingestion of infected feather dust and dry, powdered fecal material. It can be carried on clothing, hands, feeding utensils, and nest boxes.
There are three forms of PBFD. The peracute form occurs in chicks. There may be no signs and it is usually diagnosed postmortem. The acute form appears in young birds that are beginning to grow feathers to replace neonatal down. There may be several days of depression and changes in the appearance of developing feathers. New, growing feathers may die, break off or bend, and have a clubbed appearance. New feathers may be molted prematurely, before they are fully grown.
The chronic form of PBFD develops in mature birds. During each molt, more and more abnormal feathers appear. There may be bleeding in the feather shaft or within the pulp cavity of new feathers. Short, clubbed, and abnormally colored feathers may appear. Beak deformities usually occur following feather changes. The beak may become elongated and there may be fractures and necrosis of the beak. Many infected birds die within a few months of the appearance of clinical signs and a positive diagnosis. Others have been known to survive for a few years. At present, there is no vaccine or cure for PBFD.
Chlamydophila (psittacosis) is of concern to bird owners because of its zoonotic potential. Human transmission occurs by inhalation of infected particles in feather dust and/or dried powdery droppings. Birds can be aysmptomatic carriers and transmit the disease to other birds and people. There are no specific signs that a bird is infected. Many birds can carry the disease for several years, show no signs of being infected, and only become clinically ill after a period of stress. Some birds may show general, unspecific signs. There may be a lack of appetite and weight loss, lethargy and general disinterest. Bright green, watery droppings may also be apparent. There may be a discharge from the eyes and periorbital swelling. Extreme cases can cause sudden death.
C. psittaciti, the causative bacteria, has also been found in many other species of birds, not just parrots. Pigeons are assumed carriers, birds of prey, shore birds, and pet doves have been implicated, and to a lesser extent, canaries and finches. In humans, the disease is called psittacosis. This is to distinguish it from other species of chlamydia bacteria which is spread from person to person. Transmission to humans occurs in the same manner as bird-to-bird transmission; inhalation of the organism. This can come from feather dust and dried fecal material, but also from contact with respiratory secretions, handling infected birds, and by mouth-to-beak contact.
Diagnosis of the disease in birds can be difficult. Blood, serum, and swabs from the choana (the opening between the nasal and oral cavity), and cloaca (vent) swabs are submitted at the same time to a diagnostic laboratory for different evaluations. Treatment may begin if the disease is suspected, even pending laboratory results. Chlamydiophilia (in birds) and Psittacosis (in humans) can be treated with the prescribed use of tetracyclines. Confirmed cases of psittacosis are reportable to the CDC (Center for Disease Control).
TETRACYCLINE TABLETS ARE READILY AVAILABLE FOR AQUARIUM TREATMENTS. These tablets should never be used in an attempt to prevent or self-medicate. They are ineffective for anything other than fish aquaria.
The largest at-risk groups of people are bird-fanciers and pet bird owners. Other groups include veterinarians and veterinary staff, wildlife rehabilitators, pigeon fanciers, and city sanitation engineers (pigeon clean-up duty). There is no over-the-counter prevention or cure and no one is immune.
Polyoma is a contagious, fatal disease of birds. Some birds die without developing any clinical signs and others die within 48 hours of developing clinical signs. There may be delayed crop emptying, regurgitation, diarrhea, and subcutaneous bleeding.
Polyoma is readily transmitted to other birds through shared air space and contaminants (fomite) brought in on clothing, skin (from handling infected birds), jewelry, and hair. People may bring the virus into the home when visiting bird fairs or pet stores. Virus particles can survive in the environment for several months. Preventing the spread of any disease is important; this can be done by not visiting multiple bird/pet stores in the same day. People should always disinfect themselves and their clothing before handling their own birds. When purchasing a bird, never accept had all his shots. Vaccinated birds are issued a certificate by the manufacturer of the vaccine and it must be completely and accurately filled out. Vaccination will protect a bird from polyoma. Initially, the bird should receive two vaccinations given at a two to three week interval and thereafter boosted annually.
Cloacal prolapse in birds is caused by many variables, depending upon the sex of the bird. In hens, it is commonly associated with straining to lay eggs. Some cases are idiopathic, with no known cause. The recommended treatment is surgical replacement of the prolapsed tissue (Figure 14-18).
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Cloacal papillomas are common in birds. A papilloma is a benign wart that originates from epithelial cells. It can cause tenesmus (painful straining while defecating), bloody droppings, and staining of the feathers around the vent. The exact cause of papillomas is undetermined, but it is thought to be viral in origin. Birds kept in unclean environments are particularly susceptible. A simple diagnostic test can be done to determine if it is papilloma by using a dab of white vinegar on the affected tissue. If the vinegar turns the area (growth) white, it is indicative of papilloma. The acetic acid in the vinegar reacts to the papilloma tissue. Treatment may consist of surgically removing the papilloma but recurrences are common. Along with scrupulous hygiene practices, homeopathic remedies may offer some degree of relief. These treatments should not be undertaken without veterinary consultation (Figure 14-19).
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Birds are susceptible to a variety of medical problems unique to them. It is important to establish a good relationship with an avian veterinarian prior to needing emergency care.
Blood samples are most frequently collected from the right jugular vein. Most birds have a very small left jugular or no vein at all. The jugular vein is superficial and easy to visualize. The crop should be empty prior to obtaining a blood sample to prevent regurgitation and possible aspiration. Occasionally, an air sac may sit on top of the vein. To avoid inadvertent puncture, the air sac should be gently pushed aside. A 25 to 27 gauge needle connected to a tuberculin syringe is used to obtain the sample.
Blood may also be taken from the medial metatarsal vein. Collection from this site should be approached with caution as the vein is in very close proximity to the medial artery. The artery can be easily lacerated if the bird is allowed to move. Accessing this site may require anesthesia. Another potential site is the cutaneous ulnar vein, on the medial surface of the wing. Because this vein is superficial and the skin is thin, the area is easily bruised.
It is not recommended to obtain a blood sample by clipping a toenail short to make it bleed. This is very painful for the bird and the injured toe is easily contaminated. It may also cause a permanent disfigurement of the toe.
Most routine blood samples are collected in heparinized tubes. Blood volume in birds is normally 10 percent of body weight. Only small amounts are required. In most patients, 0.5 to 1.0 ml of blood will be an adequate sample. All patients should be weighed on a gram scale prior to a blood draw to determine the maximum volume of blood that can be safely taken.
Intramuscular injections are given in the pectoral muscle. Drugs administered IM need to be considered carefully, as many drugs can cause muscle necrosis at the injection site. When multiple injections are being administered, alternate sides should be used.
Fluid therapy can be administered through intravenous or intraosseous catheters or by subcutaneous injections. If giving subcutaneous fluids, the bird is restrained and one leg is pulled slightly forward and lateral. A 25 to 27 gauge needle is inserted through the thin membrane between the leg and body and the fluids are injected into the triangle formed. The fluids should appear as a small bubble forming at the site. If the needle is pushed too deep into the skin pocket, fluids may be deposited in the air sac and the patient could, in effect, be drowned (Figure 14-20).
Intraosseous catheters are placed more routinely than IV catheters because the veins are so fragile. In small birds, a 25 to 27 gauge spinal needle or injection needle is used. A 20 to 22 gauge spinal needle or injection needle can be used in larger birds. Common sites for placement include the distal ulna, proximal ulna, and the proximal tibiotarsus. Patients are anesthetized and the area is prepared with the same care as a surgical site. The catheter needle is secured by tape or sutures.
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There are many differences in avian anesthesia compared to other species. Their unique physiology affects the way they are anesthetized and monitored. Air sacs function in respiration and will have an effect on the anesthetic gas inhaled.
Birds should not be fasted for more than three hours prior to anesthesia. They have a high metabolic rate and little glycogen storage ability; withholding food for long periods can result in hypoglycemia. If the crop is full, it needs to be manually emptied prior to anesthesia induction to avoid regurgitation and possible aspiration.
Their unique respiratory system also makes birds prone to hypothermia. Heat loss occurs during anesthesia because of the constant need for air flow across the parabronchi. It is important to keep the bird warm while under anesthesia and maintain steady, positive pressure ventilation (PPV).
Inhalant anesthesia is preferred for use in birds. Injectable anesthetics are available but not used often because of the prolonged recovery and possible muscle necrosis at the injection site. The advantage of inhalant anesthesia is a quick induction and recovery time with minimal cardiopulmonary effects. Isoflurane and sevoflurane are both used successfully with a nonrebreathing system.
AFRICAN GREYS USUALLY HAVE LOWER BLOOD CALCIUM THAN OTHER SPECIES. Administering an appropriate dose of calcium gluconate by injection prior to anesthesia may help prevent seizures during anesthesia and recovery.
Birds are intubated by gently pulling the tongue forward and placing the endotracheal tube (ET) into the epiglottis, which is easily visualized at the base of the tongue. An uncuffed ET tube should be used as the tracheal rings of birds are complete and fragile. If there is an upper airway obstruction, an experienced avian veterinarian may perform an air sac intubation. It is not uncommon to experience mucous plugs in the ET tube during long procedures. If the avian patient is having difficulty breathing or the anesthetist is having difficulty ventilating the patient, the tube needs to be carefully checked for a mucous plug and immediately replaced with a new tube.
Careful monitoring during anesthesia is critical in birds. With induction, voluntary muscle activity decreases, but corneal and pedal reflexes remain. As the depth of anesthesia increases, respiration becomes more regular but vital signs continue to decrease and respiratory arrest may occur. Respiratory arrest is not uncommon in an anesthetized avian patient. With close monitoring this can be reversed or prevented. Cardiac arrest will quickly follow without immediate corrective measures. It may not be reversible. Manual ventilation and adjustment of the flow of the anesthetic agent can both help reverse respiratory arrest and establish a normal respiratory rate.
During recovery from anesthesia, the bird should be wrapped in a towel and held upright until fully recovered. Extubation occurs only when the bird is alert enough to attempt to bite the tube. Keeping the bird intubated will help prevent possible regurgitation. Most patients recover from inhalant anesthesia within five to ten minutes after the gas anesthetic is turned off. Because of their high metabolic rate, food should be offered shortly after recovery to prevent hypoglycemia.
Avian patients are usually anesthetized prior to positioning for a radiograph. This not only removes stress on the patient but also allows for better positioning, without movement and the potential of injury. The two views are lateral, with the wings fully extended and placed over the bird's back. The legs are extended caudally to expose the abdomen. The other view is ventral/dorsal (V/D). The patient is positioned dorsally with the wings spread out to either side. The legs are pulled down and away from the body (Figure 14-21).
Birds are held in position by using masking tape. White, or zonas tape, should not be used. When these tapes are removed, feathers are pulled out and there may be skin tearing.
Birds can be given nutritional support by tube feeding. The amount given is based on weight and need and placed directly into the crop. The bird is restrained with a towel and held upright. The gavage tube is gently maneuvered past the tongue and down right side towards the esophagus and into the crop. If the placement is correct, the feeding tube can be seen to slide down the esophagus into the crop. To ensure correct placement, the metal feeding tube should be felt or visualized in the crop before administering the food. If the tube cannot be felt in the crop, it is in the trachea. If the food is deposited into the trachea, it will enter the lungs and kill the bird instantly (Figure 14-22).
[FIGURE 14-21 OMITTED]
[FIGURE 14-22 OMITTED]
Parasites are rarely a concern in companion birds. If birds have parasites, they are usually ectoparasites. Knemidocoptes mite is the most common mite seen in budgerigars and passerines. This mite attacks the tissue around the cere and legs. In Budgerigars, hyperkeratosis is present around the cere. In Passerines, the legs are attacked, the feathers look ragged around the legs and the nails grow excessively. Ivermectin is the medication of choice to treat most mite infestation. Lice are not a problem in well-cared-for birds kept indoors in a clean environment. Lice can be seen along the feather shaft, close to the skin. A bird cannot contract lice from other species, including humans.
(1) How does avian respiration differ from mammalian respiration?
(2) What is the purpose of the crop?
(3) What are the methods of determining the sex of a bird?
(4) What is a blood feather?
(5) Discuss the drawbacks of allowing a bird to ride around on the owner's shoulder.
(6) List human foods which can be toxic to birds.
(7) Describe the methods of restraint used on the avian patient.
(8) Why is it so important to confirm that a feeding tube has accurately been placed in the crop?
(9) List the various types of bird feathers and the purpose of each.
(10) What is the purpose of the uropygial gland?
Bays, Teresa Bradley, Lightfoot, Teresa & Mayer, Jorg (2006). Exotic Pet Behavior. Saunders, St Louis, Missouri.
de Matos, Ricardo & Morrisey, James (2005). Emergency and Critical Care for Small Birds. Seminars in Avian and Exotic Pet Medicine, April 2005; 14(2):90-105.
Girling, Simon, DzooMed, Cbiol (2003). Veterinary Nursing of Exotic Pets. Blackwell.
Gunkel, Conny, Dr. MedVet & Lafortune, Maude (2005). Current Techniques in Avian Anesthesia. Seminars in Avian and Exotic Pet Medicine. October 2005; 14(4):263-275.
Harcourt-Brown, Nigel (2002). Avian Anatomy and Physiology. In BSAVA Manual of Exotic Pets, 4th Edition (pp. 138-148). British Small Animal Veterinary Association.
Judah, Vicki & Nuttall, Kathy (2001-2003). Tech Talk: A Look Beyond, Session I. Ronie's For The Love of Birds, Educational Seminars for Bird Owners, 2001-2003.
Kramer & Kelleher, personal correspondence 2005.
Ritchie, Branson, Harrison, Greg J., & Harrison, Linda R. (1994). Avian Medicine: Principles and Application. Wingers Publishing, Inc.
Stanford, Michael Cage (2002). Aviary Birds. In BSAVA Manual of Exotic Pets, 4th
Edition (pp. 157-167). British Small Animal Veterinary Association.
Table 14-1: Evaluation of Bird Droppings EVALUATION OF BIRD DROPPINGS Dropping consistency or color Causes Red dropping: Bright red Fresh blood from the lower GI tract Dark red Old blood from the upper GI tract "Tomato soup" or Suggests lead poisoning chocolate-appearing dropping Chartreuse green diarrhea Suggests septicemia, true diarrhea, chlyamdiosis Undigested seeds in the dropping Suggests a digestive disorder "Popcorn" looking stools Suggests pancreatic insufficiency Very large droppings in the Suggests the bird is not morning defecating overnight Polyuria (excessive urine) Suggests fruits/veggies in the diet, medication, diabetes Yellow or yellow-colored urates Suggests a liver disorder fast FACTS Avian Table 14-2 Avian Weight AVIAN WEIGHT species weight Finches 10 to 18 g Canaries 15 to 40 g Budgerigars 30 to 90 g Cockatiels 70 to 110 g Small Parrots 90 to 130 g African Grey Parrots 350 to 600 g Amazons 400 to 550 g Cockatoos 200 to 950 g Macaws 1000 to 1800 g Table 14-3 Avian Life Span AVIAN LIFE SPAN Species Life Span Finches 4 to 5 years average Canaries 8 to 10 years average Budgerigars 6 to 8 years average Cockatiels 18 to 20 years average Small Parrots 20 to 30 years African Grey Parrots 40 to 50 years Amazons 70 to 80 years Cockatoos 30 to 40 years Macaws 50 to 60 years Table 14-4 Avian Reproduction AVIAN REPRODUCTION Species Egg Incubation Time Finches 18 days Canaries 18 days Budgerigars 18 days Cockatiels 21 days Small Parrots 22 to 24 days African Grey Parrots 24 to 28 days Amazons 26 days Cockatoos 24 to 29 days Table 14-5 Avian Heart Rate/Respiratory Rate AVIAN HEART RATE/RESPIRATORY RATE Species Heart Rate Respiratory Rate Finches 274 bpm 60 to 70 breaths/min Canaries 274 bpm 60 to 70 breaths/min Budgerigars 206 to 225 bpm 35 to 50 breaths/min Cockatiels 190 to 215 bpm 35 to 50 breaths/min Small Parrots 190 to 215 bpm 35 to 50 breaths/min African Grey Parrots 147 to 163 bpm 20 to 40 breaths/min Amazons 147 to 154 bpm 20 to 30 breaths/min Cockatoos 130 to 178 bpm 5 to 40 breaths/min Macaws 110 to 127 bpm 20 to 30 breaths/min
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|Title Annotation:||UNIT III|
|Publication:||Exotic Animal Care and Management|
|Date:||Jan 1, 2008|
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