EFFECT OF SLAUGHTER WEIGHT ON MEAT PRODUCTION POTENTIAL OF WESTERN SUDAN BAGGARA CATTLE

Abstract

The study was conducted to examine the effect of target slaughter weight on feedlot performance, carcass and meat quality and the economic of meat production. Forty-eight western Baggara bulls were divided into four groups of similar body weight (164.55+3.9 kg) and all groups were intensively fed molasses based diet. The groups were randomly assigned to four target slaughter weights 200, 250, 300 and 350kg. A set of 8 external body measurements was recorded on each animal. Data on feed intake and live weight growth were collected on daily and weekly basis respectively. Bulls were sacrificed after they attained their predetermined slaughter weights. Slaughter and carcass data were collected. The quality attributes of the meat from the four groups were also carried out. Analysis of variances was used to study the effect of target weight on feedlot parameters, carcass composition and meat quality. The value of the different external body measurements in predicting live weight was carried out using correlation and regression analysis. The allometric equation in the logarithm form was used to describe relative growth of body components. The bulls on the 200, 250, 300 and 350 target slaughter weight groups took 36.1, 91.58, 152.52 and 220.5 days to reach the target weight, respectively. The results indicated that the daily gain declined significantly (P<0.05) as the live weight increased. That was accompanied by a significant deterioration (P<0.01) in feed conversion ratio. The daily dry mater feed intake proportion declined (P <0.001) as the body weight increased. Economically the gross margin and the coefficient of private profitability declined as period on feed and live weight increased. The lighter bulls revealed the highest profitability while bulls slaughtered at 350 kg consumed higher level of inputs and profit turned in a negative value. Heart girth showed the highest correlation coefficient (r =0.93) while body length scored the lowest (r = 0.65). The proportions of noncarcass components from empty body weight declined significantly (P<0.001) as body weight increased with exception of omental and mesenteric fat, which increased with the increase of live weight. Omental and mesenteric fat grew at a higher rate than the whole body. Excluding the omental and mesenteric fat, all other noncarcass components grew at a lower rate than the empty body weight (b <1). Carcass parameters such as rib eye muscle area, carcass length, leg circumference, abdominal and chest circumference, and subcutaneous fat thickness increased (P<0.001) with body weight increase. These parameters were also found to regress significantly (P<0.001) and positively with carcass weight. However, leg circumference had the highest correlation (R = 0.92) and abdominal depth the lowest (R = 0.66) correlation with the carcass weight. The dressingpercentage increased (P<0.001) with the increase of slaughter weight till 300 kg live weight and thereafter the increase was not