The effects of sire, roughage feeding condition and concentrate composition on the growth rate and carcass composition of the Japanese black steers
1997
Mitsuhashi, T. (Chugoku National Agricultural Experiment Station, Fukuyama, Hiroshima (Japan)) | Mitsumoto, M. | Ozawa, S.
Thirty three Japanese Black steers were used to determine the effect of sire, roughage feeding condition in the first half of fattening period and the composition of the concentrate in the latter half of fattening period on the growth rate, carcass composition and fat content of longissimus muscle. Steers from two sires were allocated in high and low roughage feeding groups in the first half of fattening period from 9 to 17 months of age. In the latter half of fattening period from 17 months of age to the age obtaining three target body weights, animals were fed at two concentrate compositions. The sire group differed significantly in the amount of muscle, the weight of kidney fat and the fat content of longissimus muscle. The sire group containing more muscle, had a lower weight of kidney fat and a lower fat content in the longissimus muscle. Cumulative TDN intake and the body weight at 17 months of age for R group were smaller than those for C group in the former half of fattening period, whereas the cumulative TDN intake for R group were larger than those for C group and the growth rate for the two groups did not differ in the latter half of fattening period. It was highly significant that the animals of heavier body weight at the start of fattening period reached their target body weight earlier. Carcass muscle weight and bone weight for c group were significantly heavier than those for R group, whereas carcass fat weight and fat content of longissimus muscle did not differ between the groups. The concentrate fed in the latter half of fattening period tended to cause differences in the amounts of muscle and bone. The animals in the barley fed group tended to have larger amount of muscle and bone than those in the corn fed group. Significant interactions between sire and concentrate composition on the growth rate was observed
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