Evaluation of nutritive value of local browses from Kenya on performance of growing goats (small east African x toggenburg crosses)

Abstract

The feeding value of five browse forages (Balanites aegyptiaca, Maerua angolensis, Acacia brevispica, Grewia hostii and Berchemia discolor) from semi-arid area were evaluated to check their potential as feed supplements. Rhodes grass (Chloris gayana) hay ad-libitum was used as control. The objectives of the study were to determine the feeding value of selected browses, their palatability and performance when growing goats (Small East African x Toggenburg) were offered the browse forages. Chemical composition including polyphenols and in-vitro gas production characteristics were determined. The Crude protein (CP) content ranged from 41.4gkg-1DM to Rhodes grass and 161.8 gkg-1DM in Berchemia discolor. The relative high CP content range (111.5 to 161.8 gkg-1DM) of browse forage shows the possible contribution as protein source for goats. Total extractable phenolics (TEPH) and condensed tannins (CT) contents ranged from 6.1 to 52.3 gkg-1DM and 2.0 to 43.8 gkg-1DM, respectively. Relative palatability index of local browse species and control, differed widely with the following ranking: Acacia brevispica >Balanites aegyptiaca >Grewia hostii >Berchemia discolor >Maerua angolensis >Chloris gayana. For animal performance, the intake of Rhodes grass hay (53.4, 33.0 and 37.6g/d) varied across the diets, but supplementation significantly increased total dry matter intake (53.4, 117.7 and 125.2 g/d) for those supplemented with Acacia brevispica and Berchemia discolor respectively. The apparent nutrient digestibility differed (P<0.05) among the treatments. The average daily gain (ADG) of the control animals were low with a negative value (-47.8g/d) with the supplements Acacia brevispica and Berchemia discolor having a positive gain of 21.4g/d and 22.3g/d, respectively. The supplemented diets resulted in significant changes in ADG. However, Berchemia discolor was superior among the supplements with a lot of potential as a protein supplement to low quality roughages in the arid and semi-arid areas during the dry season. In conclusion, these browses being high in nutritive value, moderate palatability and enhanced feed intake, diet digestibility and average daily gains of growing goats can be used in dry season to supplement poor quality natural pasture or fibrous crop residues to improve animal performance in the arid and semi-arid regions