Cassava meal as supplement to napier grass diets for growing sheep and goats

Abstract

Twenty growing male lambs and 20 growing male goats were used in 2 experiments to evaluate cassava meal as a supplement to chopped napier grass fed ad libitum. Four animals of each species were randomly allocated to 5 treatment groups. Cassava meal, enriched with 2% urea and 0.2% inorganic sulfur, was fed at 0.0, 0.45, 0.90, 1.35 and 1.80% of live weight. All animals received a mixture of coconut meal, rice bran and minerals to meet minimum requirements of protein and minerals. A 16-week growth trial and a 7-day digestibility trial were carried out. Cassava meal supplementation increased ( P < 0.01) ADG in both species, but differences among supplementation levels were small. Goats, fed a napier grass of lower quality, showed a larger effect of supplementation than sheep. ADG, feed efficiency and carcass weight were maximized when cassava meal represented 30% of the dry matter (DM) intake for sheep and 40% for goats. Performance decreased when cassava was fed at 50%. In terms of DM intake, cassava meal replaced napier grass on a 1:1 basis. DM digestibility increased and NDF digestibility decreased ( P < 0.05) with cassava supplementation. It is concluded that ADG can be increased by feeding cassava-urea at up to 40% of DM intake with a diet of napier grass plus a concentrate supplement of 13–17% of the total DM intake in sheep and 11–16% in goats. However, intake and digestibility of napier grass decreased at all experimental levels of cassava supplementation.