Pursuing Alternative Strategies for Healthier Medical Contraception in Dogs

Abstract

Although extensively used in the control of the reproductive cycles in either the domestic or feral dogs as well as in wild carnivores, medical progestin-based contraception still raises concerns to the veterinary practitioner and owners on its safety and efficiency. These concerns endorsed, in last decades, the research in the development of new alternatives for effective, reversible, and safe contraceptive methods for carnivores, mainly pursuing a larger-scale control of canine reproduction and the development of products with few side effects. Nowadays, the medical contraceptives often intend to master, in a reversible way, the reproductive cycle in genetically valuable dogs, which presumes that they would be active for short periods of time and ought to safeguard the animal fertility. However, hormonal contraceptives are also used worldwide to control the reproductive activity in either domestic or feral cats, for long-term treatments, because of a pretended short-term economic interest. Progestogens are the most frequently used hormonal contraceptive in carnivores. They are rather easy to obtain across the globe and relatively cheap; they have diverse drug presentations, allowing their use independently of the veterinary assistance, and are effective in preventing pregnancy. Still a significant number of undesirable health side effects are attributed to progestins when employed with some chronicity, when applied in older animals or even when misused. In the past two decades, several new approaches to managing dog reproduction were proposed to avoid progestins. However, their efficiency and cost are still to be proven as a viable alternative around the world. This chapter aims to review the medical methods available as alternative to the progestins in canine contraception, addressing particularly the future perspectives, opportunities, and limitations linked to currently available substitutes, based on our practice. This information can be of utmost interest to students, clinicians or colonies' technicians.

Manipulation of the oestrous cycle of the bitch—what works… for now

“…Megestrol acetate is an oral progestin used generally at the dose of 0.55 mg kg −1 day −1 for 32 days to a maximum of 40 days (Payan‐Carreira, Borges, & Fontbonne, ). To prevent the next cycle, treatment should be done at least 1 week before the anticipated oestrous cycle.…”