Avian reproductive tract disorders (Proceedings)

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Avian reproductive tract disorders (Proceedings)

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Apr 01, 2015

The vast majority of companion birds have not been surgically or chemically altered and are fully capable of experiencing natural hormonal influences on the reproductive tract and the body as a whole.  These hormonal influences are often inadvertently stimulated by interactions with well-intended human companions and frequently lead to undesired behaviors and serious health concerns.  Egg laying and reproduction are generally considered undesired activities for the companion bird.  Clinicians must be able to recognize factors that contribute to reproductive diseases in birds such as gender, diet, housing, photoperiod, and human interactions and instruct clients on proper diet and husbandry in order to help prevent reproductive behavior and medical problems from occurring. 

Selected female reproductive disorders

Chronic egg-laying

For the typical companion female bird, it is best if the bird lays no eggs at all.  Egg laying is considered excessive when frequent clutches or clutches with an abnormally large number of eggs are laid.  Repetitive egg laying can exhaust the oviduct and calcium stores, predisposing to oviductal inertia, egg binding, abnormal egg development, and other secondary problems such as opportunistic bacterial salpingitis and yolk peritonitis.  Chronic egg laying is most commonly seen in smaller species such as cockatiels (nymphicus hollandicus), budgerigars (melopsittacus undulatus), lovebirds (agapornis spp.), canaries (serinus canaria domestica), and finches.  Predisposing factors include an abundance of energy-rich foods, prolonged photoperiod, readily available perceived nesting sites and substrates, excessive physical and vocal stimulation from other birds or human companions, and genetic factors.

Management and prevention include providing an energy-moderate or energy-restricted diet, shortening of the photoperiod, removing perceived nesting sites and substrates, limiting physical interactions, and encouraging other activities such as foraging, target training, and play.  If these environmental and behavioral modifications are ineffective, medical intervention can be considered if the bird is considered at risk of or has developed medical complications.  Pharmacologic options include medroxyprogesterone acetate, human chorionic gonadotropin, leuprolide acetate, and deslorelin acetate, among others.  All pharmacologic options have significant limitations, risks, and disadvantages.  For example, leuprolide acetate (eg. Lupron depot 3.75-mg 1-month, abbvie, north chicago, il, usa) is very expensive, variably effective, and is very short-acting, lasting only about 2 to 3 weeks in cockatiels.  Deslorelin acetate 4.7-mg implants available in the united states for use in domestic ferrets (mustela putorius furo) for the treatment of adrenocortical disease (suprelorin f, virbac animal health, fort worth, tx, usa) have demonstrated variable effectiveness and short duration of action in avian species for the treatment of reproductive disease.  The implants are not approved by the fda but are legally marketed as an fda index drug, and extra-label use (eg. In birds) is prohibited.  Salpingohysterectomy can be considered, but the significant risks and expense of surgery generally do not outweigh the benefits for surgery in cases of uncomplicated chronic egg laying in otherwise healthy birds.

Egg binding and dystocia

A bird is considered egg bound if it has not produced an egg known to be present for longer than the normal period of development.  Dystocia is defined by mechanical obstruction to oviposition.  Most companion psittacine birds lay eggs at variable intervals greater than 24 hours, and so it can be difficult to determine with certainty if a bird has egg binding or dystocia unless the bird has been repeatedly straining for more than a few hours or if there is blood in the droppings, prolapse of cloacal or oviductal tissues, lameness, or signs of generalized illness.  Factors such as chronic egg laying, nutritional deficiency, obesity, malformed eggs, primary oviductal disease, and genetics can result in egg binding and dystocia.  Oviductal torsions and rupture have been reported in companion birds.  As with chronic egg laying, smaller bird species are more commonly affected by egg binding and dystocia. 

An egg is usually, but not always, palpable in the caudal belly when a bird is egg bound.  Eggs can be present higher in the coelom where they cannot be palpated, or can be collapsed and not detectable by palpation.  Survey radiography and ultrasonography can be very useful in further evaluating a bird for egg binding and dystocia.  Bloodwork is helpful to evaluate the bird for complications and evidence of systemic disease. Supportive care should be provided, such as fluid and nutritional therapy.  Analgesia should be provided if indicated.  Broad spectrum antimicrobial therapy should be considered if the oviduct is believed compromised or peritonitis is present or suspected.  Pharmacologic agents can be considered to facilitate oviposition, such as dinoprostone, a prostaglandin e2 (eg. Prepidil 0.5mg/3g endocervical gel, pfizer, ny, ny, usa); dinoprost tromethamine, a pgf2a (eg. Lutalyse sterile solution, zoetis, kalamazoo, mi, usa); and oxytocin.  Great caution is advised to prevent skin exposure in women with the use of pge2 drugs due to the risk of altered menses or spontaneous abortion.  Unlike pge2, pgf2a and oxytocin do not cause relaxation of the uterovaginal sphincter while inducing oviductal contractions, which may result in oviductal tears. If supportive measures and medical intervention fail to induce oviposition, manual manipulation and delivery of the egg can be attempted if the egg is present within the oviductal lumen.  Anesthesia is general advised except in the most critical patients.  Analgesia is strongly recommended. If the egg cannot be manually delivered, it can be imploded to relieve the immediate pressure, and attempts can then be made to extract the collapsed shell.  If the egg cannot be detected within the lumen of the oviduct, it may have entered the intestinal peritoneal cavity by retropulsion through the oviductal infundibulum or through an oviductal tear.  Exploratory surgery is necessary in these cases to retrieve the egg material, in which case salpingohysterectomy should also be considered.

Oviductal prolapse

Prolapse of oviductal tissues can occur as a complication to chronic egg laying, oviductal inertia, egg binding and dystocia, and space-occupying masses.  Prolapses often occur secondary to excessive or prolonged straining from undesired behaviors such as self-stimulation and from medical causes.  Treatment is aimed at stabilizing the patient with fluid therapy and nutritional support and analgesia.  The prolapsed tissues must be protected against dessication and necrosis.  The tissues can be gently cleaned with a disinfecting solution such as diluted chlorhexidine gluconate.  The tissues should be gently replaced as soon as possible.  If the tissues cannot be immediately replaced, they should be kept lubricated such as with a sterile methylcellulose gel.  Transfixing sutures across the vent opening may be necessary to keep the tissues in place after reduction.  Ensure that the bird can still defecate normally between the sutures.  Bloodwork and survey radiographs should be considered to evaluate the bird for underlying and predisposing diseases and for complications.  Sterile swabs of the prolapsed tissues can be submitted for microbiologic culture.  Broad spectrum antimicrobials should be administered based on results of culture and sensitivity testing.  Recommendations useful for the management of chronic egg laying often apply to cases of oviductal prolapse.  Nutritional deficiencies and other underlying health problems should be addressed.  Salpingohysterectomy should be considered for severe or recurring cases.

Yolk peritonitis

When yolk is present free within the intestinal peritoneal cavity, it can cause a massive localized inflammatory reaction, resulting in accumulation of free fluid, blood, and inflammatory cells.  Any disease that results in rupture of an ovarian follicle or rupture of a peritoneal egg containing yolk can result in yolk peritonitis.  Predisposing causes include cystic ovarian disease, salpingitis, metritis, oviductal rupture, reproductive neoplasia and granulomatous diseases, and oviductal torsion.  Bloodwork can be helpful to assess the bird for overall health.  Many affected birds will have severe leukocytosis and heterophilia.  Imaging through radiography and ultrasound can provide important additional diagnostic information, such as the presence of egg material or other space-occupying lesions.  Peritoneal fluid aspiration from the ventral midline can provide diagnostic material for analysis, and can also help relieve pressure from fluid accumulation.  Therapy often consists of analgesics, anti-inflammatories such as meloxicam, broad spectrum antibiotics, and other treatments aimed at suppressing reproductive activity previously described.  If peritonitis is persistent or recurrent, additional diagnostics such as laparoscopy and surgical exploratory should be considered, as well as more aggressive treatment measures such as salpingohysterectomy.

Cystic ovarian disease

Ovarian cysts have been reported in a number of avian species including cockatiels, budgerigars, and canaries.  Cysts can develop secondary to chronic endocrine disorders, anatomic ovarian malformation, and neoplasia. A genetic predisposition may be present in some birds.  Chronic reproductive behavior without egg production, or a drop in reproductive performance may be observed.  Advanced disease may be associated with signs of generalized illness or coelomic distension.  Radiographs may demonstrate polyostotic hyperostosis and a generalized increase soft tissue opacity in the coelom consistent with fluid accumulation.  Ultrasonography can be very useful in detecting free fluid and cysts on the ovary.  Cysts can also easily be visualized by laparoscopy.  Aspiration of cysts and partial oophorectomy can be considered in advanced cases.  Pharmacologic therapy may be of benefit in certain cases. 

Oophoritis

Ovarian inflammation can be caused by infectious agents or through neoplastic conditions or by extension of regionally located disease processes such as pancreatitis.  Infectious oophoritis is often cause by hematogenous or localized spread of bacteria.  Clinical signs are typically vague but often include signs of generalized illness, egg binding, cessation of egg production, and unexpected death.  Survey radiographs and ultrasonography can be useful to detect fluid accumulation in the area of the ovary. Laparoscopy can be very useful for visualizing the ovary and for collecting diagnostic samples for culture and cytology.  Treatment includes bactericidal antibiotics based on results of culture and sensitivity testing.  Pharmacologic agents such as leuprolide acetate can be helpful in temporarily shutting down ovarian activity.  A partial oophorectomy can be considered for advanced or recurrent cases.

Reproductive neoplasia

Ovarian and oviductal neoplasia are common in companion birds, particularly in budgerigars.  Clinical signs include weight loss, lethargy, inappetance, coelomic distension, left leg lameness, and dyspnea.  Reproductive complications can be seen with neoplastic diseases, such as egg binding and dystocia and oviductal prolapse.  Reported neoplasms include ovarian and oviductal adenoma and adenocarcinoma, lymphoma, leiomyosarcoma, and ovarian granulosa cell tumors.  Survey radiographs and ultrasonography can be very useful in the diagnosis of reproductive neoplasia.  Definitive diagnosis requires cytology or histopathology of excised tissues.  Treatment options include salpingohysterectomy or partial oophorectomy, depending upon the location of the neoplasm.  For many neoplasms, such as oviductal adenocarcinoma, regional invasion and postoperative recurrence are common.  Chemotherapeutic agents such as carboplatin can be considered, although no consistent results have been reported to date.

Selected male reproductive disorders

Orchitis

Testicular infections can occur through hematogenous or localized spread or through ascending infections.  Most infections are bacterial.  Clinical signs are often vague and include signs of generalized illness such as lethargy and inappetance.  Leukocytosis with heterophilia may be present.  Laparoscopy can be very useful for visualizing the testicles and for the collection of tissue aspirates for culture and cytology.  Treatment is with bactericidal antibiotics based on results of culture and sensitivity testing.  Orchidectomy is possible, either through a laparoscopic or surgical approach, but can be technically challenging and carries some risk.

Reproductive neoplasia

Testicular neoplasia is very common in male budgerigars and has also been reported in other companion avian species.  Clinical signs include lethargy, reduced appetite, loss of body condition, coelomic distension, ascites, dyspnea, and unilateral pelvic limb paresis, paralysis, or cyanosis.  Hyperestrogenemia from sertoli cell tumors can result in a color change of the cere from the blue or purple color of a male bird to the pink color of a female bird.  Diagnosis in small birds such as budgerigars can be challenging, but survey radiographs and ultrasonography can be useful.  Treatment options are very limited but chemotherapy and orchidectomy can be considered. 

Suggested reading

Bowles hl. Reproductive diseases of pet bird species. Vet clin no amer exot anim pract 2002;5(3):489-506.

Crosta l, gerlach h, bürkle m, et al. Physiology, diagnosis, and diseases of the avian reproductive tract. Vet clin no amer exot anim pract 2003;6(1):57-83.

Hadley tl. Management of common psittacine reproductive disorders in clinical practice. Vet clin no amer exot anim pract 2010;13(3):429-438.

Harcourt-brown nh. Torsion and displacement of the oviduct as a cause of egg-binding in four psittacine birds. J avian med surg 1996;10(4):262-267.

Johnston ms, gruber ej, hill ae. Retrospective analysis of risk factors for dystocia in psittacines.  Proc assoc avian vet 2010:307.

Labonde j.  Avian reproductive and pediatric disorders.  Proc assoc avian vet 2006:229-237.

Mans c, pilny a. Use of gnrh-agonists for medical management of reproductive disorders in birds. Vet clin no amer exot anim pract 2014;17(1):23-33.

Mans c, sladky kk. Clinical management of an ectopic egg in a timneh african grey parrot (psittacus erithacus timneh). J amer vet med assoc 2013;242(7):963-968.

Romagnano a. Reproduction and pediatrics. In: harcourt-brown n, chitty j, eds. Bsava manual of psittacine birds. 2nd ed. Quedgeley: british small anim vet assoc 2005:222–233.

Rosen lb. Avian reproductive disorders. J exot pet med 2012;21(2):124-131.