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A study was conducted to evaluate the effect of three mixed rations formulated using locally available feed resources on growth performance, carcass characteristic and the potential revenue returns from goats fattening enterprise in Zanzibar. Seventy two un-castrated local goats (9 – 12 months old) with initial body weight of 14.24 ± 1.39 to 14.59 ± 3.7 kg were divided into three groups of 24 animals each and were randomly allocated into three dietary treatments (D1, D2 and D3) for 90 days. Each treatment was replicated three times with eight (8) animals per replication. The three diets contained 30% concentrates and 70% roughages from three species (Gliricidia sepium, Tripsicum laxum. and Cynodon dactylon). The roughages were mixed at 10:25:35 of respectively Gliricidia Sepium, Tripsicum . Laxum and C.dactylon for D1. In D2 the corresponding mixture was 10:35:25 while for D3 it was 10:30:30. The concentrate part was formed by combination of Rice polish: Maize bran at respectively 15:5 in D1; 10:10 in D2 and 5:15 in D3. All diets also contained 5% copra cake, 4% fish meal and 1% minerals. Feed intake was measured daily whereas, weight changes were recorded fortnightly. At the end of feeding trial 9 individuals were randomly selected for slaughter. DMI was 406 ± 21.03, 406 ± 14.01, 398 ± 14.42 g/day for respectively D1, D2, D3 with no significant (p>0.05) differences among all diets. Total CP intake was 62.56 ± 3.24, 55.77± 1.92 and 63.83 ± 2.23 g/day for D1, D2 and D3 respectively; D1 and D3 being significantly (p<0.05) higher than D2. The average daily gain was 45.5 ± 9.18, 25.2 ± 11.67, 49.40 ± 14.44g/day for D1, D2 and D3 respectively. Animals in D1 and D3 had significantly higher (p<0.05) daily gain than those fed D2. Feed efficiency in D2 was significantly lower iii
(p<0.05) than D1 and D3. Animals in D2 had significantly (p<0.05) lower slaughter weight, hot carcass weight, empty body weight and dressing percentage than D1 and D3. The lean : fat was 15.1 :1, 15.8 : 1, 14.9 :1 and lean : bone ratios was 1.98 :1, 1.69 : 1, 1.64 :1 for D1, D2 and D3 respectively and ratios had no significant (p>0.05) differences among all diets. Apparent digestibility in DM and CP were 604.5 ± 65.34, 610.4 ± 41.00, 572.8 ± 48.99 g/kg DM and 585.5 ± 66.57, 536.3 ± 57.39, 555.7 ± 98.66 g/kg DM for D1, D2 and D3 respectively, there were no significant (p>0.05) differences among all diets. The economic analysis indicated that animals fed D1 had the highest net returns of Tsh. 38,721.07/goat. It is concluded that using more rice polish than maize bran in the mixed ration gave more cost effective diet and that the forage component should limit Tripsicum laxum to no more than 25%. |
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