from the Avicultural Breeding and Research Center

Introduction.

Health and medical management are important to long term care and successful reproduction of palm cockatoos. Preventative medicine with avian species is still in its infancy, but great strides have been made in the treatment of many diseases. Husbandry and diet are the basis of any preventative medical protocol for psittacines. However, there is a need for continued research in these two areas.

Physical examinations can be a major key in detecting disease in a species where signs of illness are hidden based on the survival instinct. Keeper observations regarding the activity and appetite of captive psittacines provide valuable clues in the assessment of health status and in helping the veterinarian diagnose diseases.

Physical exams, done on an annual basis during the non-breeding season, serve as opportunities to identify, monitor, and document any problems or potential problems. Basic exams include parameters such as: weight, feather condition, color of mucus membranes, locomotion, and respiratory function.

Monitoring weight losses and weight gains is helpful in detecting illness and other husbandry problems. Comparative weights taken at the yearly exam, or at a time when illness is suspected, can be a very important finding. Weight loss, despite a good appetite, may point to hidden disease. On the other hand, sometimes an increase in weight may be a sign of other diseases. Obesity, as seen in other cockatoos such as galahs and Leadbeaters, has so far not been evident in palm cockatoos. Palpation of the keel muscle and the appearance of the feet can be good guides if taking accurate weights is not feasible.

Life Span.

The life span for the palm cockatoo is unknown. Most of the birds listed in the studbook are wild caught birds acquired as adults. There are several birds that are known to be at least 30 years old or more, based on their length of time in captivity.

Sexing Techniques.

In some cases, male palm cockatoos may have a larger body size and head structure than hens, but this is not an accurate method of gender determination. In the past, surgical sexing was the most common method for sex determination in monomorphic species. Risks associated with this technique include anesthetic deaths and transmission of disease through use of improperly sterilized equipment. Surgical sexing was also of limited value in very young birds due to immature undifferentiated gonads.

New DNA sexing methods are non-invasive, accurate, quick, and safe. Only a small amount of blood is required and samples may be collected via toe nail clip or venipuncture. Stress to the bird is greatly minimized with this technology. Chicks may be DNA sexed at any age; at ABRC, samples for sexing are taken when the chick is banded.

Behavioral Manifestations of Illness.

Symptoms associated with avian illness include: loss of appetite, depression, weakness, droopy wings, change in feces or urates, fluffed appearance, and tail bobbing. Since most of the symptoms are common to a number of diseases, clinical impression and testing methods must be used to determine the best course of treatment. Keeper observations and intimate knowledge of individual attitudes and appetites are important.

Poor facial color may be a sign of illness but some palm cockatoos always have paler facial color, especially those kept indoors. Some of those kept outdoors all year will also have poor color with no detectable problems. The facial patches may turn pale or deepen to a dark reddish-purple color when the birds are stressed, such as during capture, but usually turn bright red again after the bird has been released. Palm cockatoos appear very stoic; they often do not struggle when held, making it difficult to gauge the amount of stress an individual bird experiences during capture. A change in facial color not associated with stress can be considered a potential problem and the bird should be monitored or worked up for disease if additional symptoms are present.

Medical Testing Procedures.

Medical testing procedures are very valuable tools. All newly acquired birds should be screened for infectious disease during the quarantine period. At ABRC, each newly acquired bird is quarantined for 90 days. A complete physical examination is performed, consisting of: blood chemistries, a CBC, a cloacal culture, screening for parasites, and quarantine entry weight. Blood samples are taken for PFBD and Chlamydia testing, and for DNA sexing if necessary. A routine barium radiograph is taken shortly before the end of the quarantine period for a base study. Opinions concerning a bird's health status should not be made based on the results of one test. Assess all available test results and the clinical appearance of the individual.

Parasitology

Newly acquired birds should be screened carefully for parasites using direct and fecal float tests for intestinal parasites, blood film exam for blood parasites, and physical exam for ecto-parasites, paying particular attention to the inner wing web area. Palm cockatoos should be screened for intestinal parasites on a yearly basis. It is advisable to screen birds housed with access to a dirt floor more often. Previous parasitic infection and treatment may indicate the need for additional periodic screenings for an individual bird. Patients presented for weight loss, diarrhea, and poor feather condition should be screened for parasites.

Protozoal infections, such as sarcocystis, are seen in palm cockatoos housed in areas inhabited by opossums. Sarcocystis outbreaks tend to be seasonal and death is often sudden. No accurate diagnostic test has been developed for the detection of protozoal infection antemortem.

Blood Chemistries

Blood chemistries can be helpful in assessing the bird for infections, intestinal problems, organ function, and many diseases. ABRC has performed a study to establish blood chemistry normals for the palm cockatoo (Table 1). Samples were collected from a total of 41 adult palm cockatoos, 23 males and 18 females. Prior to obtaining the samples, each bird was given a thorough physical examination and was found to be clinically normal, exhibiting no signs of illness.

Approximately 2.5 cc of blood was obtained from each bird through jugular venipuncture. Whole blood samples were preserved with EDTA. Blood chemistries were performed on serum samples using a Vet Test 8008 analyzer.

Table 1. Blood chemistry values for adult palm cockatoos. Samples were collected at ABRC in November and December of 1993. Range: ± 1 standard deviation from the mean.

Due to differences in individual birds, an adequate sample size to perform all tests was not obtained in all cases. The maximum number of tests possible was performed with each available sample.

The majority of the birds bled for the study were wild-caught adults. Six were domestically raised birds of known age. Five of these were hatched in 1989. The youngest bird bled for the project was a 1990 hatch.

In general, the blood chemistry results for these six domestic birds were similar to those of the older, wild-caught birds. Slight elevations in calcium, phosphorus, uric acid, and LDH were noted in some of the younger birds, although the individual results did fall within 2 SD of the mean level for an adult of the species.

Hematology

Identification of white blood cells is a matter of debate among many avian health professionals. Results vary from laboratory to laboratory. It is important that in an individual laboratory, all personnel processing CBCs are of the same opinion concerning the identification of various white cells. This ensures consistent results that, combined with the patient's appearance and other test results, will be of use to the veterinarian.

At ABRC, attempts were made to establish a normal range for CBCs in palm cockatoos because clinically normal individuals often have white counts on the low side of what is considered to be normal for other psittacines. Medical staff members concluded that such a study would require more data, perhaps accumulated at other facilities, for comparison. Until additional research has been performed, we should continue to work with established normals. Serial CBCs performed during the treatment of illness may be helpful in the assessment of recovery.

Microbiology

Microbiology can play an important role in the health care of psittacines, because prompt and accurate identification of pathogenic bacteria is often critical in cases of illness or injury. Gram stains of fecal smears may confirm the presence of Gram negative bacteria, which commonly cause illness in birds, but obtaining cultures is a better method of identifying species of bacteria. In addition, antibiotic sensitivity testing may be performed on bacteria grown from cultures to determine which drugs will have the greatest effect on the bacteria. Cultures and sensitivities are performed at ABRC prior to selection of antibiotics, except in critical cases requiring immediate treatment. Gram stains are performed for further clarification in some instances, but are felt to be somewhat inaccurate when performed as a single testing method. At ABRC, Escherichia coli is the most commonly isolated Gram negative bacteria species cultured from clinically normal adult palm cockatoos (Table 2).

Crop and cloacal cultures should be taken in most cases of illness. Swabs of the pharynx or the choana may be easier to obtain than a crop culture if working with an uncooperative adult bird. A tracheal swab may be indicated if the bird suffers from respiratory problems. These cultures should be plated to media that supports mycotic growth since yeast and fungus are problems for some palm cockatoos. Cultures should also be performed on wounds prior to administering treatment, if possible.

It is not uncommon for cultures taken from clinically normal palm cockatoos to grow some Gram negative bacteria. If the percentage is small and treatment is not indicated, it may be useful to take serial cultures at intervals to assess the status of the individual. Cultures of clinically normal adults are also useful because they provide a picture of the floral content of a group of birds and can be compared to cultures taken from sick birds. Gram positive bacteria found in the intestinal tract are usually considered normal flora; however, some may be problems in individual cases. In evaluating the bacteria grown, it is important to keep in mind the case and the site of the culture.

Table 2: Bacteria species isolated from clinically normal adult palm cockatoos during routine cloacal cultures taken in 1993

Culture Site - Cloaca n = 20

Radiology

Radiology is useful when treating skeletal, respiratory, or intestinal diseases. It can be used to make a diagnosis and to monitor recovery. Two views of any body part are recommended. Birds are much easier to radiograph when maintained under anesthesia; there is less chance of injury and the quality of the radiographs is enhanced.

Barium series can be done to outline the digestive tract and also to make distinctions between other organs. Double contrast studies, using barium and air, can reveal a blockage, although foreign body impaction has not been seen in palm cockatoos at ABRC. Hypaque may be used if it is desirable to highlight the kidneys.

Prior to taking barium radiographs, the bird should be fasted and water withheld for at least 12 hours. Lactated Ringers Solution may be given subcutaneously the evening prior to or directly after the procedure, if needed. Ten to 15 cc of barium sulfate can be administered into the crop using a gavage needle or feeding tube. Radiographs taken at approximately 30 minutes post administration of barium normally provide a good overview of the digestive tract. Remember that it is important to keep the bird's head elevated during administration of anesthesia, and until the bird has recovered, to prevent aspiration of the barium.

Additional Tests

Two other tests that have been helpful are bile acid tests for diagnosis of liver disease and thyroid levels, such as T4, if deficiencies are suspected.

Major Disease Problems and Treatments.

Fungal Infections

In general, adult palm cockatoos have proven to be very hardy birds but the species is susceptible to many of the same diseases that effect other psittacines. The most common disease problems seen in palm cockatoos are fungal infections. The most common fungi isolated are Aspergillus sp. A number of wild caught palm cockatoos, imported in the 1980s, died due to fungal infection. Fungal infection continues to be a problem for this group as the years go by. Treatment often requires long term therapy.

Fungal lesions have been seen in the syrinx, air sacs, lungs, base of the heart, and in major vessels. Auscultation, radiographs, hematology, blood chemistries, cultures, and endoscopy can be used to obtain a diagnosis. Treatment may include oral doses of Ancobon or Diflucan, surgical removal of lesions, and intratracheal or intravenous injections of Amphotercin B. Possible anaphylactic reactions were suspected in two palm cockatoos who died following intravenous injections of Amphotercin B. No other cause of death, including fungal infection, could be determined based on necropsy and histopathology.

Protozoal Infections

Protozoal infections are common in some areas, especially in Florida and California. These infections are often acute, and the birds are usually found dead with no previous signs of illness. Yellow urates, depression, and respiratory disease may be seen prior to death. Treatments include oral doses of Daraprim and sulfa drugs. Formulating an antemortem diagnosis is difficult if not impossible, and it is unclear if this treatment regimen is effective. The cage mate of a bird that has died of protozoal infection may be a candidate for treatment, however it is common to have only one of a pair succumb to this disease.

Gross necropsy findings typically include: very enlarged spleen, yellow fluid in the cardiac sac, and fluid-filled lungs. A quick diagnosis can be made from microscopic examination of impression smears of the lungs that have been stained using the Diff-Quik method. Sarcocystis may be diagnosed if extracellular merozoites are present.

Prevention is the best cure for Sarcocystis at this time. The use of electric fences to keep opossums off the cages, the humane trapping and removal of opossums, concrete floors in flight cages to prevent access to the ground, use of suspended cages, and regular cleaning of nest boxes are good preventative methods.

Bacterial Infections

Bacterial infections occur in most psittacines and the palm cockatoo is no exception. Symptoms often involve the respiratory or intestinal systems. Diagnosis can be made through the use of microbiology, hematology, chemistries, and radiology. Supportive care measures include: tube feeding, diet change, and subcutaneous or intravenous fluid therapy.

Some antibiotics and glucose/fluid therapies are of great value when treating the critically ill patient. Antibiotics are easily administered intramuscularly, though tissue trauma can be devastating. ABRC staff members prefer to use the subcutaneous route for this reason. Oral administration of antibiotics may be difficult when working with older or uncooperative birds.

Psittacine Feather and Beak Disease (PFBD)

PFBD infection has been observed in the palm cockatoo. Currently, there is no cure for this contagious and terminal disease, but research into the development of a vaccine is ongoing. It is possible for infected birds to live a long time with supportive care but they are susceptible to bacterial and fungal infections. A DNA probe has been developed to detect the disease prior to expression of any clinical symptoms. At this time, all birds in a collection should be tested and any birds determined to be positive based on the guidelines of testing should be removed from a psittacine collection. Young birds are particularly susceptible to this and other viruses.

Kidney Diseases

Polyuria, polydipsia, and white crystals visible under the skin are some of the symptoms of visceral gout and kidney disease. Treatments include supportive care, antibiotics, oral Allopurinol, and intravenous flushing of the kidneys. The actual cause of kidney disease is usually difficult to determine so it must be treated based on symptoms.

Serum uric acid levels can be used to detect kidney problems and to monitor progress during treatment. Dehydration may cause an increase in uric acid levels; levels may return to normal after the bird has been rehydrated.

Feather Problems

Feather cysts occur in primary feathers of the wings and tail. In many cases the cause of feather cyst development is unknown. Chronic feather cyst development may require the permanent solution of complete follicle removal.

Feather plucking or chewing is not common in wild-caught palm cockatoo but has been seen in several domestically raised, hand-fed birds. These individuals pluck coverts from the chest area, leaving the down intact.

Common Injuries and Treatments.

Many injuries to captive psittacines are prevented by providing safe, well-maintained housing and by ensuring that individual leg bands are closed bands, appropriately sized, and sturdy. Two types of injury that are more difficult for the aviculturalist to prevent are self-trauma and mate-trauma. Wing and beak trims and possible beak ball application to the male may prevent the mate trauma.

In the palm cockatoos at ABRC, the most frequently treated injury involves the beak; mate trauma is the primary cause. Self trauma, particularly during capture, can also damage the beak. The maxilla of the palm cockatoo features a thin horny layer and soft center, factors that make beak injuries common.

Bite wounds in mate traumas occur mainly to beak, mouth, and face area. However, the feet, legs, tail, back area, neck, and wings should be examined when a patient is presented after a mate attack. Scratches may be seen on the facial patches and chest area. Wounds range from minor scratches to severe, sometimes fatal injuries.

Minor beak injuries may heal well after they have been cleaned. Large or deep beak wounds can be cleaned and patched with acrylic. The patch not only protects the wound from infection but also adds stability. Patients with severe beak injury may require supportive care with fluids and tube feeding, and the administration of antibiotics and antifungals.

One palm cockatoo at ABRC lost her entire maxilla to mate trauma, leaving her sinuses exposed. The area was kept clean, and antibiotic therapy and tube feedings were administered until the area granulated in. Extreme changes had to be made in the bird's diet as she would never crack seed or nuts again. She is able to eat ground parrot pellets and ground monkey chow, and she enjoys soft fruits and vegetables. Due to the severity of her injury and the need for a special diet, this bird is not paired for breeding. Her quality of life seems to be excellent.

Mate trauma cases should be assessed for evidence of shock which could result in death if not treated. Dexamethasone SP and Solu-delta can be used for shock, along with heat and oxygen therapy. Puncture wounds to the mouth and commissures can be cleaned and ointments applied or sutured if needed. Birds with beak and mouth injuries should be removed from heat therapy as soon as possible as the warm environment could encourage secondary bacterial or fungal infections. Patients should be assessed for hypoglycemia, since some trauma victims have been deprived of food by their mates.

Overgrown maxillas and mandibles are not unusual in palm cockatoos. The maxilla tip is the most common site of overgrowth. Uneven beak wear is often noticeable, especially along the occlusal or biting surfaces of the maxilla and mandible, usually occurring on both surfaces. Treatment involves periodic trimming with a Dremel tool. The bird's appetite should be monitored after a major trim has been required. Previous beak injuries may result in overgrowth.

Toe and toenail injuries are less common, but do occur. If indicated, the wound should be cleaned and bandaged, and antibiotic therapy may be initiated. Cases of frostbite in palm cockatoos have resulted in toe mutilation. If the injury is severe, amputation of toenails or complete toes may be necessary.

Anesthesia.

The safest method of anesthesia is through the use of Isoflurane. A cone induction is the best approach, and the bird may be maintained in the cone or intubated.

At ABRC, a bird is induced at 5%, with oxygen at a flow rate of 1.5 - 2%. The Isoflurane is dropped to 2.5% - 3.5% after induction, as required. Intubated patients can be maintained at 2 - 3% Isoflurane with oxygen flow rate at 0.8 - 1%. Prior to and during a procedure, the bird's condition should be monitored carefully. It has also been pointed out that palm cockatoos are sensitive to anaesthetics from the Ketamine family of drugs. It has been reported that some European zoos feel the appropriate dose is approximately ½ the normal dosage of Ketamine. (C. King, pers. com.)

Vaccinations.

At this time no proven effective vaccines are available for diseases that occur in psittacine species.

Necropsy and Histopathology.

A complete necropsy should be performed on each bird and tissues should be submitted for histopathology. Post-mortem examination is an important tool, especially when infectious disease is suspected in a group. All organs should be examined. Tissues routinely cultured at necropsy include: heart, blood, liver, lung, spleen, and kidney. Bacterial growth from tissue cultures may be enhanced by placing the swab into an enrichment medium, such as Thioglycollate, for 24 hours prior to plating onto prepared media. Follow the SSP recommended necropsy and histopathology techniques in Appendix 15.

See Appendix 7, Drug Information for Drug Dosages

Appendix 8, Routine Physical Exam Form

Appendix 9, List of Avian Diagnostics Laboratories

Appendix 10, Microbiology Worksheet

Appendix 13, Hematology/Chemistry/Serology Records from ISIS and WOCC

Appendix 15, SSP Necropsy and Histopathology Techniques/Recommendations

For further information or comments, please contact Mike Taylor

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