THE DIGESTIBILITY AND INTAKE OF SODIUM HYDROXIDE OR LOCAL ALKALI-TREATED STRAW BY GOATS

Abstract

An experiment to compare the effects on digestibility of alkali treated Gamba grass (Andropogon gayanus) straw was conducted with four Borno white male goats (22.25 ± 1.0kg body weight) in a 4 x 4 Latin square design. Treatments were (A) untreated straw (control), (B) Sodium hydroxide (NaOH) treated straw, (C) Kanwa-treated and (D) Kantu-treated straws. Straw was treated separately with solutions (8%) of NaOH, Kanwa and Kantu for 10 minutes prior to ensiling for 20 days. In treatment A, straw was soaked in water before ensiling. Alkali treatment increased the ash and crude protein, but decreased the crude fibre, nitrogen free extract and energy contents of the silage diets. The ether extract content of the diets was not affected by treatment. Dry matter intake (g/day/Wkg ) of alkali treated diets was significantly higher (P<0.05) than the control The NaOH-treated diet was consumed less (P<0.05) than the Kantu-treated diet, but to the same extent as the Kanwa diet. Nitrogen balance was positive in animals consuming the alkali-treated diets and negative for those in the control group. Apparent N-digestibility were similar in the alkali treated diets and better (P<0.05) titan in the control. Digestibility coefficients of dry matter, crude protein and crude fibre were not significantly different among the alkali treated diets. However, they were markedly improved (P<0.05) than in the control diet (A). The results indicated that the natural alkali sources (Kanwa and Kantu) compared favourably with NaOH in improving the nutritive value of Gamba grass hay. Further work however should be undertaken to ascertain the optimal level of their application under the semi-arid environment of Borno State.