Effects of various proportions of wheat bran or pollard in sorghum grain fattening diets on live weight gain feed efficiency and carcass composition of hereford and hereford x santa gertrudis cattle
Australian Journal of Experimental Agriculture and Animal Husbandry 18(93): 469-476
A 3 .times. 2 .times. 2 factorial design was used to examine the wheat by-products pollard and bran as a replacement in all-sorghum grain feedlot diets. The by-products replaced either 10, 30 and 50% of the sorghum. Fourteen groups each of 5 Hereford steers of a mean initial shrunk liveweight of 251.5 .+-. S.E. 0.16 kg and 7 groups each of 5 Santa Gertrudis .times. Hereford cross bullocks of 391.7 .+-. 0.16 kg were used. They were slaughtered at a mean final shrunk liveweight of 407.0 .+-. 3.54 and 534.5 .+-. 5.04 kg, respectively. Production results from cattle receiving 50% by-products were significantly inferior to lower levels of by-product. There were no significant differences between 10 and 30% by-product. Cattle receiving pollard performed significantly better than those receiving bran. The growth rate of the Hereford steers of 1.24 kg day-1 was inferior (P < 0.01) to that of 1.41 for the Santa Gertrudis .times. Hereford bullocks, but the estimated gain in carcass wt of 0.75 kg day-1 was the same. The feed conversion ratio per unit of carcass weight gain favored the Hereford steers (9.91 vs. 11.95; P < 0.01), but the feed conversion ratio per unit of liveweight gain was not significantly different (6.29 vs. 6.06). The total body fat figures were comparable for steers and bullocks (mean 20.4%). Both the percentage total yield of salable meat and the percentage yield from the hindquarter were significantly greater (P < 0.01) in the Santa Gertrudis .times. Hereford cross bullocks (71.4 vs. 69.5 and 36.8 vs. 35.5, respectively).