Effects of levels of crude protein intakes on feed utilization, nutrient digestibility and nitrogen retention of growing Bach Thao goats

Abstract

The aim of this study was to evaluate effects of crude protein intake levels on nutrient intake and digestibility, nitrogen retention and daily weight gain of growing Bach Thao goats. Four Bach Thao goats at 3 months of age (10.7±1.5kg) were arranged in a Latin square design with 4 treatments and 4 periods. The four treatments were different dietary crude protein levels of 5.5, 7.0, 8.5 and 10.0 gCP/kg live weight (LW) corresponding to CP5.5, CP7.0, CP8.5 and CP10 treatment, respectively. Each period lasted 14 days, in which 7 days for experimental diets adaptation and 7 days for sample collection. The results showed that DM and ME intakes were not significantly different (P>0.05) among treatments, however CP intake was gradually significant increase (PCP10 diet (132gCP/goat/day). Crude protein digestibility was significantly higher (Pfor treatments fed with 8.5 and 10gCP/kg LW (85.1% and 87.2%, respectively), with the lowest value recorded for the CP5.5 treatment (72.7%). Although N retention increased with increasing dietary CP intake levels, the higher N retentions in the higher dietary CP intake levels did not enhance weight gain. Thus, it can be concluded that 7.0gCP/day is sufficient for growing Bach Thao goats