초록
Black Bengal goat is primarily reared for meat, skin comes here as a by-product. The present trial describes the effect of age on different carcass characteristics of Black Bengal goats of either sex. A total of 61 Black Bengal goats of different age and sex groups were slaughtered. They were reared under semi-intensive management on milk alone or with concentrates (of 10.14 MJ ME and 10.48 g M/kg DM) and freshly cut Napier grass (2 MJ ME and 25 g CP/kg of fresh matter) that provides the estimated NRC (1981) requirement. The four age groups were: pre-weaned kids (0-90 day), post-weaned kids (91-180 days), growing (181-365 days) and adult (>365 days). Goats were slaughtered according to 'Halal' method by severing the major vessels of the throat by a transverse cut. Different slaughter parameters of Black Bengal goat can be best predicted from the equations as follows: live weight (kg)=0.801 (shoulder height (cm))-24.32, ($r^{2}$=0.94); carcass weight (kg)=0.364 (height at hind legs (cm))-11.54, ($r^{2}$=0.91); edible weight (kg)=0.623 (shoulder height (cm))-19.94, ($r^{2}$=0.91) and saleable weight (kg)=0.701 (shoulder height (cm))-21.99, ($r^{2}$=0.92). Live weight, carcass weight, edible weight and saleable weight of castrated goat at one-year onward ranges from 20-22, 9.4-10.5, 14-16 and 16.6-18.8 kg, respectively, which are about 80% higher than most of the reported observations on Black Bengal goat of same age and sex. Slaughter weight, warm carcass weight, edible weight and saleable weight increased curvilinearly with age of slaughter but not affected (p>0.05) by sex. However, linearity of the response curve of affect of age on mentioned parameters ends at around 9 months. Visceral fat as per cent of live weight increased curvilinearly with age and attain its maximum (about 6%) at about 500 days. However, linear part of the quadratic model ends at about 300 days when visceral fat content is about 4.8% of body weight. Blood and skin yield for one-year old male goat was 797 g and 1.61 kg, respectively. Absolute yield of blood and skin increased curvilinealry and attained maximum level at about 400 days (13.3 months). Average proportion of different carcass cut were - round 27%, rump 7%, loin 10%, ribs (6-12th) 14%, shoulder 21%, Neck 7%, chest 14%. Thigh and shoulder constituted about 48.3% of the cold carcass weight. Overall crude protein content of meat samples of different carcass cuts progressively decreased with age starting from 57 at 0-90 days to 58, 47 and 33 per cent, respectively at 91-180, 181-365 and >365 days, respectively. Overall meat fat content increased almost linearly from 11.1% during 91-180 days to 22.9 and 39.5% during 181-365 and >365days, respectively. Results from this trial suggest that both carcass yield and carcass composition changes with age; and sex have little or no effect on carcass yield and carcass composition. However, caution should be made in using second conclusion as there were few female animals slaughtered relative to the male. Optimum slaughter age for Black Bengal goat reared under semi-intensive management with adequate feeding and management would be about 9 months when their live weight, warm carcass weight, edible and saleable weight of carcass can be about 16.74, 7.28, 12.05 and 13.81 kg, respectively.