Nutritive value of browses as protein supplement(s) to poor quality roughages

Abstract

In tropical and subtropical regions, pasture grasses and cereal residues are frequently low in nutrients especially protein and therefore cannot support high levels of ruminant production. Many browse species are endowed with high levels of protein and hence suitable as supplements. The objective of this study was to develop indices that could be used to predict nutritive value of browses as supplements to poor quality roughage basal diets. Experiments were carried out to address issues related to establishing an experimental protocol for screening large browse species in feeding trials, the effect of animal species and the proportion of browse in the diet. Different methods to estimate protein digestion in small intestine were compared and data of individual browses collected. The palatability method developed was suitable for evaluating palatability of large numbers of browses under stall feeding condition. If palatability is done to predict long term intake a period of 5 to 8 days should be allowed. Classification of browses using either chemical composition, degradability or gas production characteristics led to different cluster groups than when palatability was used. Tannins had beneficial attributes at moderate levels and detrimental effect at high levels. The optimum level of browse supplementation was 30 to 45% of the ration dry matter. Browses need to be further studied since some of the secondary chemicals contained may affect reproduction