Fertility control in a male rabbit using a deslorelin implant. A case report

Abstract

Continuous low-dose release of the GnRH analogue deslorelin (Suprelorin, Peptech, Australia) causes a suppression of reproductive function in different species such as dogs, koalas, or kangaroos. No studies concerning the effi cacy and safety in male rabbits have yet been conducted. A male rabbit with hypospadia was introduced to the Clinic for Animal Reproduction. The owner intended to keep it together with a fertile female rabbit. To avoid reproduction, a 4.7 mg deslorelin implant was injected subcutaneously. No negative reaction to implant placement was diagnosed by daily examination of the injection site for one week. To test the effectiveness of the treatment, blood samples were taken and the testes size was measured regularly. After an initial rise in testosterone levels for 14 d, a down regulation for seven month with values lower than 0.1 ng/mL was observed. In the same period, the size of the testes declined to 50 % of the original dimensions. Afterwards, both testes regained their former shape and size. Since it was not a stud rabbit, semen parameters were not determined. During the suppression of the reproductive function, no sexual activity was observed by the owners. These fi ndings have yet to be proven by clinical trials with a suffi cient number of animals, but this case indicates the effi cacy of deslorelin implants in male rabbits.