The value of whole cottonseed in a wheat-based maintenance ration for sheep

Abstract

The effects of fuzzy whole cottonseed (WCS) on the performance and health of sheep were examined. Thirty 2-year-old Merino wethers were divided into 3 equal groups and offered maintenance rations for 138 days, with whole wheat grain to WCS ratios of 100:O (diet A), 75:25 (B) and 50:50 (C). Liveweight changes for diets A, B and C were -0.3, +4.4 and +3.0 kg respectively, and were significantly (P<0.05) greater on WCS diets. Wool growth rates were also significantly (P< 0.01) improved by the addition of WCS, with treatment means being 0.65 (diet A), 0.82 (B) and 0.88 mg/cm2.day (C). Digestibility of DM in diet C (677 g/kg) was significantly (P< 0.001) lower than in diets A (782) and B (777 g/kg), perhaps because of increased fibre and oil in the ration. Subclinical anaemia and muscle damage were evident in animals given WCS by days 43 and 127 respectively. Post mortems and histological examination revealed renal haemosiderosis in sheep given WCS, with increased severity at 50% inclusion in the ration. Despite the reduction in digestibility and the subclinical effects on health, at least 25% WCS can be safely included in a wheat-based maintenance ration for wethers and this ration has production advantages over wheat alone. Caution is advised in feeding higher levels of WCS or feeding such a ration for more than 5 months.