By L. Chenor. University of Alabama. 2018.
Those that do The nares and operculum (keratinized plate inside occur are generally caused by granulomas or neo- the nostril) should be smooth generic robaxin 500mg fast delivery, relatively dry generic robaxin 500 mg amex, symmet- plasms, and early detection and surgical correction rical and evenly sized and colored. The (ducks), the nares are located within the beak, while ear canal may be hyperemic in birds with sinusitis. The feather configuration around the nares var- species; however, the surface of the beak should be ies among species. Cockatoos have dense feathers smooth, shiny and uniform regardless of the species. By comparison, The occlusal surface of the upper and lower beak Amazon parrots have sparse bristle-type feathers should meet at midline and be even throughout the around the nares. In Amazon parrots, the nares are surrounded by bristle feathers and are located at the edge of the skin margin and the beak. In some species, like this owl, and in Anseriformes, the nares are located in the beak and may not be surrounded by feathers. Serous discharges are usu- ally associated with respiratory irritants while mucopurulent dis- charges are most commonly associated with infectious agents. In free-ranging birds, the beak is main- indicate a previous or ongoing sinus infection (see tained in good condition through exposure to mois- Chapter 22). Physical damage (bite wounds) to the ture followed by drying from exposure to sunlight. As epithelial growth centers of the beak can cause simi- the bird eats and chews on woody plants, the dry lar lesions. Proliferative growths associated with the outer edge of the beak is removed, which maintains beak are common with Knemidokoptes sp. Dry, flaky layers on the beak and skin around the Oral Cavity cere are abnormal and may signal poor management Evaluation of the oral cavity can be augmented using or systemic disease (Figure 8. Birds that fre- a speculum or gauze strips to open the mouth (Figure quently bathe, are fed formulated diets and have 8. A detailed examination of the oral or pharyn- regular exposure to fresh air and sunlight have fewer geal mucosa may require isoflurane anesthesia. In ad- mulation of mucopurulent discharge in the dition to rhinitis, the bird also had diarrhea palatine area of a conure with hypovitami- and mild tremors. A tenacious, mucopuru- nosis A and bacterial sinusitis and trachei- lent discharge was noted in the pharyngeal tis. A correctly healed bird’s was changed from an all-seed to a formu- beak (left) is shown for comparison (cour- lated diet. Because the bird’s wings Note the ulcerations and scab formation had been improperly trimmed, the bird (courtesy of Patricia Macwhirter). After feather regrowth, sented with a two-day history of depression and blood-tinged feces. Veterinary assis- surgical debridement of the wound and re- moval of the necrotic portion of the sternum tance was requested when frank hemor- rhage was noted in the feces. The trochlear Severe obesity in a Screech Owl that was groove (arrow) is visible through the skin. Note that the keel is not visible, damage (right) associated with medial and accumulated fat is bulging into the luxation of the Achilles tendon (courtesy of thoracic inlet area. Traditionally, tattoo ink is injected into the right propatagium of males and the left propatagium of females. The ear canals can be evaluated for discharge or for abnormal have been suggested as causes of this problem in accumulation of desquamated hyperkeratotic skin by parting the cockatiels. Some birds (particularly Respiratory Tract Passeriformes) may have brightly colored spots in For examination purposes, it is easiest to divide the the mouth that play a role in brooding activities. The respiratory system into the upper respiratory tract tongue has a dry sheen while the choanal slit and (sinuses and trachea), lungs and lower respiratory pharyngeal and laryngeal mucosa are slightly moist tract (thoracic and abdominal air sacs). Choanal papilla are well formed in in severe respiratory distress may require oxygen some species (Amazon parrots and macaws) and less before it can tolerate the stress of a physical exami- distinct or absent in other species (Color 8. If the bird is calm and does not struggle Accumulations of debris or food, abnormal coloration, during the physical examination, the respiratory erosions or ulcerations, sticky white mucus or rate will generally remain constant. In these birds, perichoanal, pharyngeal or sublingual swellings are the respiratory rate should be increased by gently abnormal. White plaques that are easily removed holding the feet and moving the hand in a downward and blunting or swelling of the choanal papillae are motion. This will stimulate wing flapping and should common with hypovitaminosis A (Color 8. In a normal bird, the low yellow or white plaques that are attached and respiratory rate should return to its pre-exercise rate difficult to remove are common with pox or bacterial within two minutes of ceasing the exercise. White or brown cheesy le- tained tachypnea can indicate respiratory disease, sions are suggestive of candidiasis or trichomoniasis cardiovascular disease or a mass that is blocking air (Color 8. Birds with these lesions A pediatric stethoscope is ideal for auscultating the are frequently infected with Candida sp.
Duck Virus Enteritis) lacrimation order robaxin 500mg amex, anorexia generic 500 mg robaxin with amex, cyanosis and greenish, watery (occasionally hemorrhagic) diarrhea. Mature birds Duck plague virus seems to be distributed worldwide generally have a more prolonged course of disease. Af- herpesvirus that does not cross-react with other fected free-ranging waterfowl may sit on the water avian Herpesviridae. Suggestive lesions include pete- Susceptibility varies considerably according to the chia and ecchymosis on the epicardium (see Color host species and virulence of the virus strain. Nonspe- characterized by somnolence, lethargy, anorexia, ruf- cific lesions include necrotic foci in the liver and fled plumage and intermittent diarrhea, polyuria hemorrhage of developing egg follicles. Biliverdin staining of liquefied feces and urates is indicative of the severe Histopathologic examination reveals eosinophilic in- liver necrosis caused by the virus (see Color 8). Si- tranuclear inclusion bodies (Cowdry A type) in hepa- nusitis, hemorrhagic diarrhea, conjunctivitis and tocytes, bile duct epithelial cells and the epithelial convulsions or tremors in the neck, wings and legs cells of the cloacal and esophageal mucosa. Many outbreaks Muscovy Duck, erosions may be observed in the tran- are linked to a stressful event such as a change in the sition zone between the proventriculus and ventricu- environment or the onset of breeding season. With peracute or acute disease, birds are in generally Since its initial description, there have been numer- good condition at the time of death. A massively ous cases of a Pacheco’s-like disease induced by a swollen, tawny, light-red or greenish-colored liver herpesvirus. The spleen and kidneys are also hosts include macaws, Amazon parrots, conures, Af- distinctly swollen, and the intestinal mucosa may be rican Grey Parrots, Poicephalus spp. Histologic lesions include ries of the genus Eos, parakeets of the genus Psit- congestion, hemorrhage and coagulative necrosis of tacula, cockatoos, budgerigars, King Parrots and the hepatocytes. Patagonian and Nanday Conures are fre- is often misleading, because birds frequently die quently discussed as asymptomatic carriers that in- from massive liver necrosis before an inflammatory termittently shed virus; however, any bird that re- reaction occurs. If gavage administra- tion is not practical, the powdered acyclovir can be added to the food at a dose as high as 240 mg/kg. Acyclovir may cause considerable nephrotoxic- ity, and this drug should be adminis- tered carefully in patients with neph- ropathies. The role that acyclovir may play in inducing asymptomatic carriers has not been determined. Other species may Grey Parrots and Blue and Gold Ma- survive an infection and become asymptomatic carriers. The instructions for use provided by the manufacturer should be carefully followed. Radiographs indicated an enlarged liver that occupied much of the abdomen and displaced the proventriculus dorsally and caused the caudal border of the heart to appear indistinct. At necropsy, the liver was enlarged (three to four times normal), mottled, red and had numerous subserosal hemorrhages. Histopathology confirmed the presence of hepatocellular necrosis and intranuclear inclusion bodies suggestive of Pacheco’s disease virus. The virus is occasionally recoverable from parenchymatous or- gans, blood or feces. Decreased egg hatchability is the principal problem associated with this virus, which is serologically related to the pigeon herpesvirus, but not to Pacheco’s disease virus or related strains. A herpes-like virus was reported in a Yellow-crowned Amazon that died acutely following exposure to budgerigars. At necropsy, the thickened crop mucosa showed parakeratotic lesions with basophilic in- tranuclear inclusion bodies in the epithelial cells. Cells of the exogenic pancreas revealed degeneration accompanied by the formation of syncytial cells. In addition, chronic hepatitis and proliferation of reticular cells in the spleen were noted. In infected flocks of English Standards, breeding should be interrupted to allow hens to develop immunity, which should provide some protection for the chicks. The host spectrum of this virus is uncertain, but pigeons and budgerigars are known to be susceptible. Annual outbreaks have been described Small, grayish-greenish diphtheroid foci on the mu- in some flocks. Transmission can occur through con- cosa of the upper airways, pharynx and occasionally tact with contaminated feed or water, through direct the crop and intestine are characteristic necropsy contact between mates and through parenteral feed- findings. This virus may also induce only Clinical Disease, Pathology and Diagnosis necrotic hepatitis. Serous rhinitis and conjunctivi- Histopathology reveals necrosis (liver, kidney, pan- tis are usually the first clinical signs of disease.
Adrenocortical failure and shock may occur in birds exposed to one or more stressful situation following iatrogenic glucocorticoid administration generic robaxin 500 mg without a prescription. Exposure to high doses over a pro- turbances in feather formation of unknown etiology robaxin 500 mg online. Replacement therapy is indicated in length, which controls the neurohumoral factors. Neural control of feather formation has been demon- strated by growth retardation of feathers when de- Stress Marks nervation occurs. The metabolic processes that un- A common disorder of developing feathers is the sym- derlie feather formation are regulated by the thyroid metrical development of stress marks or hunger and the gonads. The presence of thyroid hormone, however, is essential for the growth, differ- In some birds (eg, Galliformes, Passeriformes, An- entiation of structure and formation of feather pat- seriformes), feather color and pattern vary with the tern. The importance of thyroid hormone for feather age, gender and season, and these characteristics are formation is generally similar in young and mature governed by hormonal influences of the gonads. In some birds, this thyroid dependence affects these birds, the adult plumage, unlike the juvenile the rate of feather growth and formation of vane plumage, develops under the influence of at least two structure and in others, it affects the pigmentation endocrine glands. In these birds the plumage does not change under influence of In thyroidectomized birds, the lower parts of the plasma concentrations of sex hormones but is gov- feather are underdeveloped, while in hyperthyroid- erned by the autosome: sex chromosome ratio and ism, these parts develop most vigorously. The roidism, the vanes of the feathers are narrower and influence of sex hormone in the former group in each there is a partial reduction of the barbs. In a number feather-forming process is realized only at a defini- of fowl breeds, hypothyroidism is accompanied by tive level of metabolism that is maintained by thy- partial or complete replacement of black eumelanin roid hormone (female plumage does not develop in by brown pheomelanin, while in hyperthyroidism thyroidectomized birds given estrogen). The black pig- bird is adequately saturated with thyroid and sex ment can be formed in the bird’s body at only a hormones, the feathers that develop should be certain concentration of thyroid hormone. Under conditions of hypothyroidism or athyreosis, the feathers that de- Molting is possible only as the result of complex velop are uniform in structure and should be termed hormonal influences. Molting occurs during a period the athyreoid type of plumage (and consequently also of depressed sexual activity. The male plumage is potentially an attribute of both genders, and the female hormones play the principal When the duration of light is decreased, or a long role in gender differences in the plumage of Gallifor- period of artificial daylight is suddenly replaced by a mes and Anseriformes. When a rooster, drake or cock short one, sexual activity declines or ceases and molt- pheasant is castrated, no changes are produced in the ing begins. When a ods of daily light associated with declining sexual castrated rooster or a neutered hen undergoes an activity are needed for the proliferation of feather ovarian transplant, female-type plumage develops. Sudden transi- tion to darkness after prolonged exposure to length- ened periods of daily light produces vigorous molting in various birds. It should be remembered that many avian species Diabetes Mellitus must be exposed to natural photoperiods to allow a normal hypothalamic-pituitary control of the molt- ing process. Improper photoperiods may be an impor- Spontaneous diabetes mellitus has been reported in tant cause of feathering disorders in companion birds a variety of granivorous avian species, including the kept indoors. One case of spontaneous diabetes ment requires that appropriate nutrients for feather 103 mellitus has been reported in a raptor. A tentative diagno- body’s increased requirements of thyroid hormone in sis can be made by demonstrating glucosuria while a connection with the development of new feathers. Glucocorticoids, epinephrine, There are some striking differences between birds glucagon and growth hormone can all induce hyper- and mammals with respect to pancreatic control of glycemia and impaired glucose tolerance. The insulin content of the duction of these hormones may occur with tumors of pancreas of granivorous birds is about one-sixth that the hormone-producing cells or paraneoplastic syn- of mammalian pancreata, while the glucagon content dromes (“ectopic” hormone production). Circulating plasma concentrations of glucagon are 10 to 50 times higher In man, hyperglucagonemia may be associated with in birds than in mammals. In mammals, pancreatec- bacterial infections, trauma, congestive heart fail- tomy results in diabetes mellitus. Reported effects of ure, azotemia and functioning tumors of the α-cells pancreatectomy in birds are controversial. However, of the islets of the pancreas or of the gastrointestinal recent experiments performed on granivorous birds tract (eg, glucagonoma). The few reported pancreatec- secondary invasion usually via serosal implantation tomies performed on carnivorous birds have always on the duodenal loop of tumors arising in the female reproductive tract. The limited data available on was identified as an α-cell adenoma has been de- spontaneous diabetes mellitus in granivorous birds scribed. The cellular There are several case reports of successful treat- origin of the tumor was not identified, but it was ment of spontaneous diabetes mellitus in birds with suggested that it could be an α-cell tumor. Glucagon concentrations on the The normal avian pancreas contains extremely high other hand were extremely high or extremely low. Neoplasms associated with this syn- may have previously laid eggs and then stopped be- drome include lung carcinoma (oat cell and small cause of the egg-related peritonitis. Numerous cases suggest that any carci- noma may induce an ectopic endocrine syndrome. Experimental administration of pro- raptorial bird was associated with markedly vacuo- lactin to Mallard Ducks results in a decreased urine lated B-cells indicative of excessive stimulation.
9 of 10 - Review by L. Chenor
Votes: 173 votes
Total customer reviews: 173