Effects of different protein sources in the diets on feed intake, nutrient digestibility and nitrogen retention of pregnant Bach Thao goats

Abstract

Four female Bach Thao goats (live weight of 29.9±0.20 kg) at the first month of pregnancy were arranged in a Latin square design with four treatments and four periods to evaluate effects of different sources of crude protein (CP) in the diets on feed intake, nutrient digestibility and nitrogen retention. The four treatments were crude protein sources from coconut meal (CM), soybean (SB), soybean extraction meal (SEM) and Sesbania grandiflora leaves (SGL) corresponding to CM, SB, SEM and SGL treatments, respectively. Para grass (Brachiaria mutica) was offered as the basal diet for goats and different amount of urea was supplemented in the diets to ensure goats to consume the targeted CP intakes of 6.0 gCP/kg live weight. Each experimental period lasted for 14 days, which consisted of 7 days adaptation and 7 days of sample collection. The results showed that DM intakes were significantly higher (PSGL treatments (883 g/goat/day) than the other treatments, while CP and metabolized energy (ME) intakes were not different among treatments (P>0.05), which ranged from 156 to 166 g/goat/day and 6.37 to 7.18 MJ/day, respectively. The DM digestibility were higher (Pthe SGL treatments (73.7%) while CP digestibility and nitrogen retention tended to be higher (P>0.05) for the SB treatment (85.2% and 18.6 g/day, respectively). The daily weight gain was not significantly different (P>0.05) among treatments with the highest gain for the SB treatment (134 g/day) and the lowest for the SGL treatment (112 g/day). Results of this study suggest that all the four CP sources used could be used for the feeding of pregnant Bach Thao goats. However, the use of the locally grown Sesbania grandiflora leaves should be of advantage in term of cost.