Effect of dietary crude protein levels on the performance of lactating cows

A study was conducted to assess the influence of level of dietary protein on early lactation in crossbred cows. 18 cows divided into 3 equal groups were offered concentrate mixture containing either 26.6 (T₁), 20 (T₂) and 16.9% (T₃) CP supplemented with paddy straw in 30:70 ratio for 100 days. The total DM intake of animals in the T₁ group was lower (P<0.01) than that of the other two groups. The digestibility coefficient of EE, CF, NDF and ADF were significantly higher (P< 0.01) for the T₁ ration. There was no significant difference in the milk production, milk composition or blood parameters except blood urea nitrogen, among the groups. The blood urea nitrogen levels of the 50^th day collection was significantly higher (P< 0.01) in the T₂ group than that of the T₃ group. Rumen pH and lactic acid content were high (P< 0.05) in T₁ group while NH₃-N concentration was low (P<0.05) in the animals fed T₃ ration. The cost of producing one kg milk was Rs. 7.79, 7.91 and 7.71 for the three groups, respectively. Results suggested that CP level of 16.9 per cent in the concentrate mixture was sufficient to meet the requirements of cows in early lactation, producing a peak of 10 kg milk per day.