Growth rate, apparent nutrient digestibility and some blood metabolites of Gwembe valley goats on rations based on crop residues in the hot dry season in Zambia.

Twelve Gwembe goats (9 females and 3 males; 12-18-months old; average body weight 18.50 +/- 0.05 kg) were divided into three groups and fed complete rations based on crop residues. Three residues of oilseeds--bambara groundnut shell (BGS), groundnut shell (GNS) and sunflower head (SFH)--were used. The rations were isonitrogenous and isocaloric. The average daily dry matter intake was BGS 0.85 +/- 0.02, GNS 0.88 +/- 0.02 and SFH 0.89 +/- 0.03 kg/head per day, which did not differ from each other significantly (p > 0.05). However, the daily live weight gains were significantly different (p < 0.05). Goats that consumed SFH gained more (84 g; p < 0.05) in live weight than those fed BGS (76 g) or GNS (72 g). Feed conversion followed the pattern of live weight gain. The plasma non-protein N values were 25.1 +/- 0.36, 24.6 +/- 0.38 and 24.9 +/- 0.35 mg/100 ml, while the plasma glucose concentrations were 67.2 +/- 1.44, 65.1 +/- 1.32 and 67.8 +/- 1.49 mg/100 ml, respectively, for goats on BGS, GNS and SFH rations, with no significant difference (p > 0.05) between the three rations. The cost/kilogram for each of the rations were all within the same range, but the cost/kilogram of live weight gain was lower for the SFH ration than for the GNS and BGS rations. The nutrient digestibilities of the crop residues were similar among the treatments. Overall, SFH tended to perform better than GNS or BGS in these complete rations for goats in the hot dry season.