Alternatives to surgical neutering in dogs, cats and small mammals

Surgical neutering is the most common procedure performed in small animal practice. Due to various reasons, however, there is a wish and need for effective medical alternatives. This article provides a summary of licensed substance groups/formulations and presents further off label indications where clinical expertise exists with regards to contraception and/or suppression of the oestrous cycle. Progestins are the classical alternative to surgery, but as antiandrogens they are not suitable for safe contraception in male animals. Melatonin may effectively suppress the feline oestrous cycle for about two months and additionally, has a negative short-term influence on semen quality in torn cats. Slow-release GnRH agonist implants are suitable for long-term contraception in male and female dogs, cats, ferrets and rats, as well as female rabbits and guinea pigs. All castration-related effects and side effects can only be observed following application of the GnRH agonist implant, making this method the only option for "test castrations" In female animals, initial oestrus induction must be principally taken into account and in bitches the application needs a strict indication and should be restricted to young, sexually healthy animals.