Otters are popular exhibit animals that present a reproduction management challenge; on one hand, otters are often kept in groups, necessitating contraception. However, specific individuals may be required to breed, but have low reproductive success. In other carnivore taxa, such as canids and felids, subclinical histopathological lesions of the reproductive tract may be a significant cause for infertility or subfertility. Lesions in the endometrium are frequently associated with exposure to endogenous and/or exogenous ovarian hormones in canids and felids.1-2 However, the literature on reproductive endocrinology and reproductive histopathology for otters is scarce.
The goal of this study is to evaluate the reproductive tracts of several species of otters, both contracepted and non-contracepted, in order to determine if contraception status plays a role in reproductive pathology in female otters. Preliminary results suggest that otters as a group may have a propensity for endometrial hyperplasia regardless of contraception status, as 80% of the otters currently in this study (16/20) have some degree of endometrial hyperplasia. Age may also be a factor, as 56% of otters currently in this study with moderate to severe hyperplastic change (9/16) were geriatric (≥10yrs). A better understanding of naturally occurring lesions, as well as the lesions associated with exogenous hormones, will allow managers to improve breeding success, overall health, and safety and potential reversibility of contraception.
1. Moresco, A., L. Munson, I.A. Gardner. Naturally occurring and melengestrol acetate-associated reproductive tract lesions in zoo canids. Vet Pathol. 2009;46:1117–1128.
2. Munson, L., I.A. Gardner, R.J. Mason, L.M. Chassy, U.S. Seal. Endometrial hyperplasia and mineralization in zoo felids treated with melengestrol acetate contraceptives. Vet Pathol. 2002;39:419–427.