Pediatric medicine is an important facet of avian practice. Veterinarians working with birds will need to learn the normals of chicks of different species, such as times that the eyes and ears open, when pinfeathers come in and when birds wean, in order to accurately advise their clients. If you are fairly new to the practice of avian medicine, it would benefit you, as an avian practitioner, to hand-raise a few birds, to actually experience the whole process. The baby bird that you hand-raise can be your clinic bird, perhaps housed in the reception area, to let your clients know that you have an interest in birds and avian medicine.
Physical examination of the neonate requires that the baby be kept warm during the check-up. Neonates with only down feathers cannot thermoregulate and will chill quickly. Consider keeping one exam room warmer or place a heating pad or Thermofloor on the exam table for additional warmth.
Systematic examination of the neonate can be performed in a similar fashion to that of an adult bird. Note the color of the skin, and the texture. Some babies, such as the eclectus parrot, have pigmented skin. Pale skin may signify anemia, malnutrition, chilling, shock or polyomavirus.
Evaluate the size of the head and beak in relation to the body. Examine the musculoskeletal system for symmetry, straightness, deviations, annular toe deformities or healed fractures. Some of the internal organs are visible through the translucent skin, including the liver, supraduodenal loop of the intestine, yolk sac and lungs. Examine the umbilicus and abdomen. The ventriculous will be seen as a bulge that is palpable and firm. Auscultate the heart and lungs.
Check the beak for symmetry, lateral deviations, mandibular prognathism, bite wounds, other abnormalities, and note the color. In most species of birds, the egg tooth is shed between days 26-44. Using a light source and magnification, check the oropharynx for lesions, foreign bodies, plaques and note the color. Blue and Gold macaws usually have a black-pigmented oropharynx, but some will lack pigment in patches, which can resemble candida plaques or other pathology.
Examine the eyes for discharge, swelling, symmetry, or scabbing. Abnormal placement of the eyes under the lids can indicate stunting. Eyes usually open between 10-28 days of age, depending on the species. Always evaluate the ears. Ears open at hatch in Old World Species, and macaw ears open at approximately 23 days. Macaws and eclectus have their external ear canals covered with a membrane at hatch. Infection of the ear canals is fairly common in stunted macaws.
The nares should be closely examined for swelling, discharge, or erythema. The crop should be examined for tone, movement, foreign bodies, which may be palpated within the ingluvies, and the consistency and volume of contents should also be palpated.
Neonatal down is small and fluffy and may lack a rachis. Chicks will then develop a secondary growth of juvenile down, called the second down. Check that the feathers are emerging properly. Note any stress bars, hemorrhage in the feather shafts, abnormal colors, or any feather deformities.
Next, check the baby for the feeding response. In a normal neonate, by gently touching the beak in certain specific locations, usually the rictal areas, the feeding response will be elicited. In sick, cold or weak babies, the feeding response will be weak or absent.
Evaluating the history is critical. Always ask the owner to bring in growth/weight records for review. A healthy neonate should gain weight daily, then level off, and ultimately lose approximately 10-15% of its body weight at weaning. The nursery environment and husbandry must be evaluated. It is important to know if a neonate is being kept at the correct temperature and humidity for its age and size. The container and substrate are important considerations, as they may contribute to management-related diseases and conditions. The hand-feeding formula, utensils, and their handling and storage need to be evaluated. Problems can arise from the hand-feeder making the formula incorrectly, or by the improper cleaning of utensils and hand-feeding equipment.
Any diagnostics that can be performed on adult birds may be performed on neonates. Gram's stains are valuable as a quick screening method for identifying potential problems, however, bacterial cultures should be performed in conjunction with a CBC to confirm suspected infections. Gram's stains should not be relied upon solely for diagnosis of disease in birds. Fungal cultures are often helpful in differentiating pathogenic Candida versus brewer's yeast in formula. Blood chemistries and serology are also useful diagnostic tools. Radiographs are a helpful diagnostic device. When radiographing young birds, make sure that the crop is empty, to prevent regurgitation and subsequent aspiration of hand-feeding formula. The proventriculous is proportionately larger in hand-feeding babies than it is in adult birds.
Drawing blood from the leg vein
Blood may easily be drawn from the right jugular vein, or from the medial metatarsal vein. It is not advisable to clip a toenail short on a baby bird to get a blood sample, as it is possible to permanently damage the tissue, resulting in a deformed toenail. Testing for PBFD, polyoma, chlamydia and other diseases should be performed.
Developmental and husbandry problems may occur in baby birds. Stunting of chicks is manifested by poor growth rate or failure to thrive. It may occur as a result of poor husbandry, the inexperience of the hand-feeder, inadequate husbandry, underlying disease or as a result of poor incubation technique. It may be reversible. Leg and toe deformities are frequently seen. Neck problems may be corrected by the use of a padded neck brace or by taping the neck to the side of a container.
Lateral deviation of the maxilla occurs most frequently in macaws, but is occasionally observed in other species. Mandibular prognathism, also called maxillary brachygnathism, occurs most frequently in cockatoos, but may be seen in other species. Early discovery of beak deformities will facilitate easy correction. Physical therapy and corrective grinding may be corrective in cases that are discovered early, but orthodontic devices or prosthetics may be necessary to correct beaks that have already hardened.
Gastrointestinal problems are the most common disorders of neonates, and may be related to improper husbandry, disease or metabolic disorders. Most systemic diseases in chicks result in slowed gut transit time, reflected by a crop that empties slowly. Aviculturists may call this "sour crop," which is a catch-all phrase. Respiratory problems occur most commonly as a result of aspiration of hand-feeding formula.
Bacterial infections are commonly seen. It must be remembered that little pharmokinetic data has been published for drugs in hatchlings, nestlings and fledglings. Several factors affect pediatric therapy, including liver dysfunction, renal disease or dehydration.
By far, the most common viral disease seen in the nursery is polyomavirus. Only chicks hatched at a facility should be raised in the nursery. If aviculturists purchase or trade chicks with other facilities, their nursery can never be managed by other than a crisis-to-crisis basis. A DNA PCR blood test is available for this virus. Psittacine Beak and Feather Disease, PBFD, is common in psittacine chicks. A DNA PCR blood test is available, and requires a clean venipuncture stick, and not a toenail clip, for accurate testing. Proventricular Dilatation Disease, PDD, and avian viral serositis, AVS, also occur.
Traumatic problems may occur. Hepatic hepatomas may occur from blunt trauma. Wounds may occur from bites. Constricted toe syndrome occurs most commonly in eclectus and macaws. Crop burns usually occur by food being fed too hot (over 110 degrees F.) Allow these to scab and fistulate prior to surgery, as surgery performed too soon will result in dehiscence. Esophageal punctures may occur from improper tube feeding. These will often result in cellulitis, toxemia and death without surgery. Fractures are uncommon in healthy chicks. Concussions may occur in birds that are fledging. Feather trauma may occur.
Wine-colored discoloration of urates occurs in juvenile amazons, African greys and pionus, and is not associated with disease. "Lock-jaw" may occur in cockatiel chicks, as well as in other species, and is caused by bacterium, Bordetella avium.
Necropsies of dead baby birds are very important. The same tissue harvested for adult bird necropsies should be taken, with the addition of the bursa, which is located near the cloaca in the celoem. This organ is vital for the diagnosis of many avian diseases and should always be included for histopathology.
Avian pediatric medicine and surgery is a fascinating and challenging aspect of avian medicine. The same principles that apply to adult birds may usually be applied to neonates, with the exception of surgery and anesthesia. The rate of oxygen consumption in neonates is 2-3 times greater than adults, and the respiratory rate is also 2-3 times that of adults. Cardiac output is rate dependent because sympathetic innervation of the heart is immature, and bradycardia can be a serious problem if not detected and reversed. This is more likely to occur after 10-15 minutes of anesthesia. Blood loss is of greater consequence in neonates, and they are less able to compensate for hemorrhage, and a small volume of blood loss can result in tachycardia and hypotension. Featherless neonates must be kept from developing hypothermia. With any surgical procedure: use isoflurane, use careful anesthetic monitoring, use rapid surgical technique, limit surgical time to 15 minutes or less, and maintain total hemostasis.
Copyright © 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
All Rights Reserved
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