Practical relevance: Reproduction control is an area of feline medicine that is assuming increasing importance in companion animal practice. Signs of oestrus such as increased vocalisation, rolling on the ground and a very short interoestrous interval may negatively influence the relationship between cat and owner, and prompt the owner to seek a method of reproduction control. In breeding catteries, control of reproduction may be needed as part of a planned breeding programme.
Clinical challenges: Surgical contraception is not always the owner's wish - especially when a cat may be intended for future breeding. Besides, ethical principles and animal welfare legislation in an increasing number of countries are imposing restrictions on this 'classical approach' to reproduction control. Progestins are routinely used as non-surgical alternatives in cases where fertility is to be preserved, but the associated risks of uterine disease, mammary tumours, fibroadenomatosis or diabetes mellitus have to be taken into account - especially in predisposed animals. Modern, effective pharmacological alternatives are available for managing oestrous suppression and unwanted pregnancy. Detailed knowledge of the physiology of the oestrous cycle in the cat is necessary to ensure that the appropriate treatment is chosen for the individual animal and its owner.
Audience: This article presents an update for small animal practitioners on these alternative methods; specifically, the use of slow-release GnRH agonists or melatonin implants for hormonal contraception, and the antiprogestin aglepristone for pregnancy termination.
Evidence base: Several studies have documented the mode of action and risk of side effects of the traditional alternative to surgical castration - treatment with progestins. Evidence underpinning the safety and efficacy of GnRH agonists and melatonin implants for suppression of fertility in queens and toms is reviewed.
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