Effects of Supplementary Feeding on Reproductive Functions of Small Ruminants

Abstract

Animal nutrition and reproduction are two major components that are interrelated. To increase animal production, manipulations of those components should be emphasised. Many earlier findings have indicated that nutrition could alter reproductive functions by changing the body metabolic status or by increasing body reserves status of the animal. These two effects of nutrition are known as the 'dynamic' and 'static' effects. Increased animal production, with emphasis on animal nutrition, is reviewed (Chapter 2) in several stages of the animal's life (ie. cyclic or oestrous, pregnant, lactating and anoestrous). Also the manipulation of the reproductive system by the manipulation of reproductive hormones is discussed in relation to increased productivity. The use of several exogenous synthetic reproductive hormones indicate that there are possibilities for improving some reproductive traits both with and without any concern with the nutritional status of the animal. When on animal is in the stage above critical level (ie. above maintenance) and the availability of feed is not a problem, improvement in productivity may be possible, whilst additional attention to nutrition is necessary for improvement when feed is inadequate. In this thesis a series of experiments is reported and most of these experiments were carried out in the field, stressing the effects of protein supplementation.