Abstract
The application of rumen undegradable intake protein (UIP) on lactating dairy goats was studied. Thirty 2-year-old lactating dairy goats were selected and assigned to dietary treatments begun from the third week to the fourth month postpartum. Experimental diets were formulated into three, low (32% CP), med (35% CP) and high (38% CP), iso-nitrogenous (16% CP) and iso-energetic ($NE_L$ 1.68 Mcal/kg) UIP levels. Results showed that feed intake was not significantly different among the treatment groups. The milk yield in the High UIP group (3.17 kg) was significantly higher than the med (2.95 kg) and low UIP (2.45 kg) groups (p<0.05). The milk compositions, milk fat, milk lactose and milk solids-non-fat (SNF) showed no significant differences among the three treatment groups. The milk protein however was significantly (p<0.05) lower in the low UIP than in the other treatment groups. The milk urea-N was significantly (p<0.05) higher in the low UIP than in the other treatment groups. The mean serum aspartate amino transferase (AST), urinary-N and total protein concentrations were significantly (p<0.05) lower in the high and the med UIP groups than in the low UIP group.