STUDIES ON THE PROTEIN REQUIREMENTS OF GROWING QING GOATS

Zhong Cheng, Fang Guoxi, Li Fengshuang ( Agricultural University of Shandong )

Four month age Qing goats (33 heads) were used in this experiment to study the protein requirements of growing goats. A feeding trail and a N-balance trail were designed for determining EUN and MFN. With low-N ration the EUN of the goat is 0.121g/w0.75, MFN is 0.151g/w0.75 or 0.56g/100g DMI, which are in agreement with the results of the others'. From the N-balance data it is known that the content of protein has little effect on the digestibility of other constituents of the diet, but its digestibility is affected by the other nutrients, espcially DE and NFE. The result of Path Analysis indicates that the general effect of DE oh nitrogen digestibility is the largest. By the Least Square Method of Variance Analysis and other analysis methods it is found that protein is the main factor affecting gain and that the general effect of DE is the second one. But the appropriate protein level is 8.5% which means that the group II is the ideal one. Based on the results of this experiment, the protein requirements of young Qing goat for minimum maintenance is 1.51g DCP/W0.75, the maintenance requirement is 2.92g CP/W0.75 or 1.79g DCP/W0.75, the requirement for gain is 0.56gCP/g or 0.35g DGP/g. From all these data the protein requirement equation for growth can be obtained as follows: CP(g/day) =2.92W0.75 + 0.56g gain.