Abstract

Edinburgh Zoo has lost several breeding female king penguins (Aptenodytes patagonicus) over the past few years due to oviduct prolapses. When cases were detected early, prolapses were reduced and secured with a purse string, and penguins were treated with an anti-inflammatory drug and an antibiotic. Pathologic findings from four postmortem examinations did not identify a definitive or common cause but did suggest that these cases of oviduct prolapse could be seen as a sequela to egg laying.

Introduction

Oviduct prolapse may occur secondary to egg laying, physiologic hyperplasia of the oviduct, or as a sequela to dystocia. Underlying causes include deformed eggs, malnutrition, or obesity. Underlying causes may be ruled out through submission of samples for bacterial culture and sensitivity and through radiography.

Treatment varies and depends upon the underlying cause and the amount of protruding tissue present. Part of the oviduct may be protruding with vaginal and cloacal tissue. Treatment includes removal of an egg if present, reduction of the swelling in exposed tissue, and maintenance of oviduct-vaginal patency. The prolapsed tissue should be replaced after cleansing and a purse string applied or cloacopexy performed to prevent reoccurrence.³ Medical treatment includes broad-spectrum antibiotics, nonsteroidal anti-inflammatory drugs, nutritional support, and medication to decrease hormonal levels (e.g., leuprolide acetate, medroxyprogesterone or human chorionic gonadotropin).² Surgical treatment is an alternative with salpingohysterectomy.¹ Prognosis is generally good after treatment of most prolapses, and return to normal breeding function may be accomplished in most birds as long as underlying predisposing factors are identified and eliminated.^5,6

Methods

Edinburgh Zoo houses four species of penguins in its zoological collection: gentoo penguins (Pygoscelis papua papua), rockhopper penguins (Eudyptes crestatus moseleyi), macaroni penguins (Eudyptes chrysolophus), and king penguins (Aptenodytes patagonica patagonica).

King penguins are fed 8–10 herrings per day and supplemented from February through September with two multivitamin tablets (Mazuri™ fish eater tablet, Witham, Essex, UK), one vitamin B1 tablet (Benerva, Roche, Welwyn Garden City, UK, 100 mg), two cod liver oil tablets (Isoactive, Edinburgh, UK, 400 mg), and one vitamin E tablet (Millpledge Pharmaceuticals, Retford, Notts, UK, 1000 mg). Vitamin B1 and vitamin E are not supplemented during the remainder of the year (a practice currently under review).

Breeding success has been variable within the king penguin colony. Last year, one male chick was successfully hand-reared. The breeding success has been partially hampered by the death of females due to oviduct prolapses. Prolapses have occurred infrequently in the past and have been noted in other zoological collections (personal communication, E. Flach, 2004). This problem did not occur with the other penguin species held within the collection at Edinburgh Zoo. In the majority of cases, the king penguin females were found dead; however, minor prolapses were detected in a few females at an earlier stage.

A portion of the oviduct was protruding with vaginal and cloacal tissue in a few cases in king penguins. When identified, the prolapse was reduced and a purse string suture was placed. The penguins were treated with an anti-inflammatory drug (carprofen, Rimadyl™, Pfizer Ltd., Sandwich, Kent, UK, 4 mg/kg IM BID) and an antibiotic (enrofloxacin, Baytril™, Bayer PLC, Strawberry Hill, Newbury, UK, 10 mg/kg, PO BID). Itraconazole (Sporanox™, 20 mg/kg, PO SID) was given prophylactically to prevent against aspergillosis. In the majority of incidences, the oviduct was presumed to have prolapsed during the night, as the animal was found collapsed or dead in the morning. Penguins that showed a mild prolapse the previous season had a lethal prolapse the following 1–2 years.

Full postmortems of the four cases seen since 2000 were performed at the Lasswade Veterinary Laboratory Agency (Pentlands Science Park, Penicuik, UK) and have been summarized in Table 1. No routine bacterial cultures were performed on reproductive tissue of postmortem specimens. Salmonella screening was performed routinely on liver and intestine and was negative in all cases.

Table 1. Summary of postmortem evaluation for king penguins (Aptenodytes patagonicus) with oviduct prolapse at the Edinburgh Zoo, 2000

^aA longitude tear was found in the oviduct wall and may account for the egg in the pelvic cavity.
^bHematology was normal at that time. Bacterial culture at that time isolated a heavy mixed growth of Escherichia coli and Enterobacter cloacae and a scant moderate growth of Candida albicans.

Results and Discussion

No common denominator could be identified as to the primary or underlying cause for the oviduct prolapses. Various parameters such as age, diet, husbandry, and disease were reviewed in each case. None of the birds were related. Keymer (1980), in his overview of the disorders of the avian female reproductive tract, states an unusually high percentage of affected penguins (close to 25%), probably due to the high number of older birds and evidence of hypovitaminosis A.⁴

Of the four birds, only one (24 years) falls into the former older age category. Longevity in captivity reaches approximately 30 years. Obesity, another contributing factor to reproductive problems, was only noted in one bird (19 kg). The average recorded weight for king penguins at Edinburgh Zoo is 12–13 kg.

Pathologic findings suggest that these cases of oviduct prolapse could be seen as a sequela to egg laying. Breeding cycle in the wild is every 2–3 years as parents take 15–18 months to raise their chicks. Breeding is more intense in captive breeding programs with cycles every 1–2 years.

Acknowledgments

I thank the pathologists at VLA Lasswade, the penguin keepers at Edinburgh Zoo, and colleagues at the exotic animal service.

Literature Cited

1.  Bennett, R.A. and G.J. Harrison. 1994. Soft tissue surgery. In: Ritchie, B.W., Harrison G.J. and L.R. Harrison (eds.): Avian Medicine: Principles and Application. Wingers Publication Inc., Lake Worth, FL. Pp. 1096–1136.

2.  Bowles, H.L. 2001. Diagnosis and management of female avian reproductive disease. Proc. Ann. Conf. Assoc. Avian Vet. 2001: 349–357.

3.  Joyner, K.L. 1994. Theriogenology. In: Ritchie, B.W., Harrison G.J. and L.R. Harrison (eds.): Avian Medicine: Principles and Application. Wingers Publication Inc., Lake Worth, FL. Pp. 748–804.

4.  Keymer, IF. 1980. Disorders of the avian reproductive system. Avian Pathol. 9: 405–419.

5.  Orosz, S., Dorrestein, G.M. and B.L. Speer. 1997. Urogenital disorders. In: Altman, R.B., Clubb, S., Dorrestein, G.M. and K. Quesenberry (eds.): Avian Medicine and Surgery. W.B. Saunders Co., Philadelphia, PA. Pp. 614–644.

6.  Romagnano, A. 1996. Avian obstetrics. Semin. Avian Exotic Pet Med. 5: 180–188.