Effects of cowpea cultivar supplementation on productivity of Pedi goat and Dorper sheep fed Ad Libitum buffalo grass

Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2010

Two studies were carried out to investigate the effect of cowpea cultivar supplementation on productivity of Pedi goats and Doper sheep fed ad libitum buffalo grass. Experiment 1 investigated the effect of cowpea cultivars supplementation on productivity of Pedi goats fed ad libitum buffalo grass hay using twelve goats that were assigned in a completely randomized design. The Pedi goats were fed ad libitum a basal diet of buffalo grass supplemented with four levels each of four cowpea cultivars namely, Pan 311, Red caloona, Black eye and Agripes. The four levels fed were 50, 100, 150 and 200 g/day. The experiment involved a 25 day preliminary period and a five day collection period during which feed intake, digestibility, live weight changes and nitrogen were measured. Based on available data, all the cowpea cultivars contained more than 15 % crude protein and can therefore be used as protein supplements to goats on low quality roughage. Pan 311 had higher feeding value (p<0.05), although it contained the highest concentration of condensed tannins. The concentration of tannins in Pan 311 did not exert negative effects on intake and digestibility. The data on a in vitro enzymatic digestibility of the cowpea cultivars and buffalo grass hay demonstrated that the cowpea cultivars had higher in vitro DM, OM and protein digestibilities that ranged from 0.64 to 0.75. The cowpea cultivars have high in vitro digestibility values thus implicating their suitability as supplements. Also chemical contents of the cowpea cultivars and the buffalo grass hay had poor capacity to predict forage in vitro digestibility. Forage intake and growth rate of Pedi goats were poorly predicted from in vitro digestibility. Experiment 11 investigated the intake and relative palatability indices of four cowpea cultivars offered to Pedi goats and Dorper sheep fed low quality buffalo grass hay. The experiment was a 2 (animal species goats and sheep) x 5 diets (four cowpea cultivars and buffalo grass hay) factorial arrangement in a completely randomized design. Intake and palatability of the goats and sheep were higher in Pan 311. Sheep had higher voluntary feed intake values than goats, but palatability indices were higher in goats than in sheep. Goats were better than sheep in the palatability indices ranking of the four cowpea cultivars. This seems to demonstrate that goats are better suited for assessing palatability indices ranking of cowpea hays and other similar legumes. Forage intakes and palatability indices ranking were poorly predicted from their nutrient. Growth of the goats was well predicted by forage in vivo digestibility and palatability indices. Also, forage intakes accurately predicted the palatability indices of the cowpea cultivars by the goats and sheep.