ผลของระดับโปรตีนในอาหารข้นต่อการเจริญเติบโตและการใช้ประโยชน์ของโภชนะของแพะพื้นเมืองไทย เพศผู้

Abstract

Two experiments were conducted to evaluate the effects of protein levels in concentrate on intake, growth, nutrient utilization, nitrogen (N) balance and protein requirement for maintenance and growth of Thai Native male goat fed with pangola hay. Experiment 1: Effects of protein levels in concentrate on growth performance and nutrient utilization of post weaning (3–6 months old) Thai Native male goat were studied. Sixteen Southern Thai Native male goats with average body weight of 8.20 ± 2.70 kg, were allocated into 4 treatments under a Completely Randomized Design (CRD) for 100 days study period. Treatment diets consisted of pangola hay ad libitum supplemented with concentrate at 2% of body weight (BW) as dry matter (DM) basis. The crude protein (CP) levels in concentrate were 8, 10, 12 and 14% of DM, respectively. There was no effect of CP levels in concentrate on the amount of hay, concentrate and total feed intake, including digestibility coefficient of dry matter (DM), organic matter (OM), CP and Total digestible nutrient (TDN) (P>0.05). Increasing CP content in the concentrate significantly (P<0.05) increase amount of CP intake (4.49, 5.23, 5.86 and 6.56 g/kgBW0.75/d, respectively), digestible CP intake (2.73, 3.30, 3.72 and 5.14 g/kgBW0.75/d, respectively), N balance (0.31, 0.39, 0.48 and 0.67 g/kgBW0.75/d, respectively) and blood urea nitrogen (3.71, 4.38, 6.07 and 8.81 mg%, respectively). Increasing CP content in the concentrate resulted in linearly (P = 0.011) increased average daily gain (ADG) of goats (20.83, 31.48, 30.56 and 40.28 g/d, respectively). The results of the regression of CP intake (CPI) on ADG showed that Southern Thai Native male goat needed 3.13 (±0.31) g/kgBW0.75/d or 17.60 g to maintain their BW. The estimation of CP requirement for goat BW gain (g/g) was 0.39 (±0.05) or 37.10 g for weight gain at 50 g/d. Experiment 2: Effects of protein levels in concentrate on growth performance and nutrient utilization of growing Thai Native male goat (6–12 months old) were studied. Sixteen Southern Thai Native male goats, with average BW of 11.50 ± 2.10 kg, were allocated into 4 treatments under a CRD for 190 days study period. Treatment diets consisted of pangola hay ad libitum supplemented with concentrate at 2% of BW as DM basis. CP levels in concentrate were 8, 10, 12 and 14%, respectively. There was no effect of CP levels in concentrate on the amount of hay, concentrate and total feed intake, including digestibility coefficient of nutrients (DM, OM, CP and TDN) and N balance (P>0.05). Increasing CP content in the concentrate significantly (P<0.05) increase amount of CP intake (5.76, 6.48, 7.00 and 7.96 g/kgBW0.75/d, respectively), digestible CPI (2.71, 3.30, 3.68 and 4.10 g/kgBW0.75/d, respectively) and blood urea nitrogen (7.78, 11.45, 16.38 and 21.16 mg%, respectively). Increasing CP content in the concentrate resulted in linearly (P = 0.013) increased ADG of goats (37.96, 51.74, 52.78 and 56.25 g/d, respectively). The results of the regression of CPI on ADG showed that Southern Thai Native male goat needed 1.71 (±0.84) g/kgBW0.75/d or 16.17 g/d to maintain their BW. The estimation of CP requirement for goat BW gain (g/g) was 0.72 (±0.14) or 52 g for weight gain at 50 g/d.