Reproduction of goats in the tropics and subtropics

Abstract

Goats are widely found in tropical areas and are used for meat, milk, fiber and hide production. Improvement in their reproductive efficiency is important for increasing the productivity under the tropics. Local goats display interesting reproductive characteristics : most of them can reach puberty at an age of 8 months, have the ability to breed all year round and have a relatively short post-partum anœstrus. However, there exists a strong environmental influence which does not allow these potentials to be fully expressed. In particular, insufficient nutrition is often responsible for the appearance of prolonged anœstrous and anovulatory periods, a reduction in fertility and prolificacy and also causes an elevated off spring mortality rate. A repeatable seasonal influence, presumably through photoperiodic signals, is found in European imported breeds and also in the local goats of some subtropical areas. The use of the male effect allows to induce œstrus and ovulations during periods of reproductive inactivity and to increase overall fertility. In areas where a strong seasonal pattern is observed, its use is not sufficient to obtain a good fertility level and it is necessary to couple it with techniques to reduce the seasonal effect ; photoperiodic manipulations could be used for that purpose.