Nattapon Pengbunsom, Surasak Kochapakdee, Wanwisa Ngampongsai, and Taweesak Niyombundit

pp. 1187 - 1197

Abstract

       The research were to study the effect of protein levels in concentrate and genotype on carcass characteristics and carcass composition of 12-13 months male goats receiving corn silage as a roughage. A 2x3 factorial in completely randomized design was used with two factors; genotype of goat (Thai-native (TN)
and 50% TN-Anglo Nubian (AN) crossbred goats) and protein levels in concentrate (14, 17 and 20% CP). Carcass weight and carcass length for 50% TN-AN goats (13.86 kg and 52.41 cm) were significantly greater than those for TN goats (10.97 kg and 48.17 cm) respectively (P<0.05). Goats supplemented with 14, 17 and 20% CP concentrate were not significantly different in carcass weight, carcass percentage or carcass length respectively (P>0.05). Percentage of shoulder and neck for goats supplemented with 20% CP concentrate
were significantly greater than those for goats supplemented with 14 or 17% CP (34.99, 32.24 and 32.52% respectively, P<0.05). However, percentage of shank for goats supplemented with 17% CP concentrate was significantly greater than that of goats supplemented with 14 or 20% CP (7.96, 7.34 and 6.37% respectively) (P<0.05). Percentage of shoulder and neck for 50% TN-AN goats was significantly greater than those for TN goats (33.92 and 31.91% respectively, P<0.05). In contrast, percentage of breast in carcass for TN goats was significantly greater than those of 50% TN-AN goats (8.41 and 7.29% respectively, P<0.05). Fat contents in carcass of TN goats were significantly greater than those in 50% TN-AN goats (8.66 and 6.80% respectively, P<0.05). But bone in carcass of 50% TN-AN goats were significantly smaller than those in TN goats (16.20 and 18.77% respectively, P<0.05). However, muscle to bone ratio and muscle plus fat to bone ratio for TN goats were significantly greater than those for 50% TN-AN goats (4.34, 3.71 and 4.87, 4.08 respectively, P<0.05).
        Net income after subtracing the total cost for goats supplemented with 14, 17 or 20% CP concentrate was 183, 150 and 175 baht per head respectively. Net income after subtracing feed cost for TN and 50% TN-AN goats was 162 and 174 baht per head respectively. Net carcass income after subtracing total cost for
goats supplemented with 14, 17 or 20% CP concentrate was 415, 382 and 523 baht per head respectively. Net carcass income after subtracing total cost for TN and 50% TN-AN goats was 364 and 510 baht per head.