Growth, Herbage Utilization and Meat Production in Japanese Black and Brahman Sired Crossbred Cattles

点击翻译按钮获取中文摘要

This study was carried out to examine whether an introduction of the germ plasm of Brahman(Z) breed was effective or not for improving the herbage utilization, physiological fundtion and growth potential of Japanese beef cattle.1. Blood components and circulating levels of hormones were evaluated for 1/4Z, 3/4 Japanese Black(B) and BB heifers in the term of grazing and housing, and genetic differences in their traits were determined. Blood samples were taken in July and Octorber and eight houres before and after feeding of concentrate, and clinical screen of blood chemistries, IGF-1, T3 and Insulin were measured. 1/4Z was higher in cholesterol level and lower in trigricerid and total protein levels than BB in any terms. There were no breed-group differences in IGF-1 and T3.1/4Z tended to be higher than BB in insulin response after feeding of concentrate, but in the corresponding response of plasma glucose, there was no breed-group difference.2. Daily gain(DG), herbage utilization and behavior in grazing were evaluated for calves of 1/4Z(3/4B), BB and Japanese Shorthorn(NN). NN was larger in DG than 1/2Z and BB, but there was no difference between 1/2Z and BB.NN was higher in fiber digestibility of July than other two, but there were no differnces among breed groups in herbage intakes per metabolic body weight and dry matter and protein digestibillities. In grazing beheviour, there was a difference between July and Octorber, but no differences among breed groups. As reasons of these results, the following two points were suggested, (1) breed charaacteristics were not shown by one group grazing of all calves, (2) releasing amounts per a day of chromic oxide capsule given for the estimation of herbage intakes were not constant in term of grazing.