Dry Acacia sieberiana pods as a supplement to a low quality forage diet for growing lambs in northern Nigeria.

Abstract

Twenty yearling lambs of mixed breed were grouped according to initial liveweight (20 +/- 2.7 kg), and each group was offered one of 5 concentrate rations as a supplement to a low quality, dry season Andropogon gayanus hay. Voluntary food intake and liveweight change were monitored over a 56 day growth period, after which 5 of the lambs were transferred to metabolism crates, in which digestibility and nitrogen balance studies were carried out. Ground Acacia sieberiana pods were substituted for maize offal in the experimental diets A, B, C, D and E at 0%, 15%, 30%, 45% and 60% respectively. Mean group intakes and growth rates were (913, 964, 1020, 1128 and 1004 g conc. DM/day) and (111, 120, 149, 165 and 119 g liveweight gain/day) respectively. A decline in both intake and growth rate were recorded as the level of A. sieberiana was increased beyond 45% of the supplement. This corresponded to a daily dry matter intake of Acacia pods in excess of 500 g, or 43 g/kg W0.75. This decline may have been due to the toxic effects of the phenolic compounds present in Acacia. It appears that up to a certain critical level of intake, A. sieberiana is able to support growth rates equal to or better than those obtained when feeding maize offal to lambs. This makes A. sieberiana an attractive low cost alternative, supplementary feed during the dry season.