Estimation of energy and protein requirements of Qianbei brown goats during early gestation

The objective of this study was to determine the energy and protein requirements of Qianbei brown goats during early gestation. Thirty-six 2^nd parity Qianbei brown goat ewes with similar body weight (27.45 ± 0.29) kg and gestation times (30 ± 3) d were randomly divided into four groups each including three replicates with three goats per replicate. Ewes were fed 60%, 80%, 100%, and 120% of nutrient requirements. After 10 d of adaptation, all ewes were fed for 30 d while collecting their feces and urine output to measure nutrient utilization during the final 7 d of the 30 day feeding period. Regression equations fitting energy/protein intake and body-weight/daily gain were established to estimate energy and protein requirements for maintenance and growth of Qianbei Brown goats during early gestation. Gross energy intake (GEI), digestible energy intake (DEI), metabolizable energy intake (MEI), crude protein intake (CPI), digestible protein intake (DCPI), and metabolizable protein intake (MPI) in Qianbei brown goats improved with increasing nutrient levels, and average daily body weight gain (ADG) of Qianbei brown goats also increased. ME requirements for maintenance (ME_m) and growth (ME_g) of Qianbei brown goats in early gestation were 447.10 kJ·kg⁻¹ BW^0.75 and 29.80 kJ·g⁻¹, respectively. DCP requirements for maintenance (DCP_m) and growth (DCP_g) were 2.75 g·kg⁻¹ BW^0.75 and 0.22 g·g⁻¹, respectively. In conclusion, nutrient intake and growth were enhanced with increasing nutrient levels, and both energy and protein maintenance and growth requirements of goats were similar to those recommended by the USA National Research Council.