Effects of protein nutrition levels on milk yield, composition, amino acid profiles and plasma metabolites of indigenous lactating buffaloes

Abstract

The dietary crude protein (CP) supply was optimized for indigenous lactating buffaloes in Bangladesh. Twelve buffaloes (age 4 yr) with an average daily milk yield of 2.33–3.03 kg/d and average ± SD body weight of 390 ± 10 kg were divided into three groups (each with four animals) that were randomly assigned to three levels of CP in the concentrate feed mixture: 14.22%, 15.62%, and 17.81% (dry matter basis) in a completely randomized design. The total duration of the study was 100 d with an initial 10 d of adjustment. The diets were formulated to ensure the same energy level. The dietary protein level showed no effect on dry matter intake (p > 0.05). The nitrogen intake of buffaloes increased linearly (p = 0.01) with increasing CP levels. The milk yield tended to increase in a quadratic fashion. No effect was observed (p > 0.05) on the milk protein, fat and lactose contents. The level of plasma urea nitrogen increased
(p < 0.05) when the dietary CP levels were raised, whereas the glucose, protein, albumin, globulin, calcium and triacylglycerol levels remained unchanged (p > 0.05). The nitrogen efficiency of lactating buffaloes increased (p < 0.05) by optimizing dietary protein nutrition accurately to each animal’s requirements. The milk amino acid composition was unaffected (p > 0.05) by the dietary CP supplies. In conclusion, the 15.62% CP level resulted in higher milk production (p < 0.05) and high nitrogen efficiency (p < 0.05) in the indigenous lactating buffaloes under the study conditions.