Effect of paddy straw plus non-forage fibre sources based complete feeds containing different levels of neutral detergent fibre on digestibility coefficients of nutrients in lactating dairy cows

摘要

A study of six months duration was conducted to assess the effect of paddy straw based complete rations containing different levels of NDF on digestibility coefficients of nutrients in lactating dairy cows, in two phases, viz., early and mid lactation. Three isonitrogenous and isocaloric complete rations, T1, T2 and T3 with 25, 30 and 35 per cent NDF, respectively were formulated as per ICAR (1998). Paddy straw was the sole source of roughage NDF, with the rest of NDF being met from non-forage sources, in all the three rations. Eighteen dairy cows yielding approximately 10 kg of milk per day were divided into three groups of six each, and allotted to the three experimental rations. There was no significant difference (P0.05) in digestibility coefficients of nutrients such as dry matter, organic matter, crude protein, crude fibre, ether extract, nitrogen free extract, NDF and energy, among the dietary treatments, in both phases I and II. However, the digestibility coefficient of acid detergent fibre was significantly higher (P0.05) in T2 and T3 than T1, with T2 and T3 being similar (P0.05), in both the phases. A thorough evaluation of the results obtained in the present study, reveal that the animals in all the three dietary treatments performed well, with the complete rations T3 with 35 per cent NDF and T2 with 30 per cent NDF showing better performance than T1 with 25 per cent NDF. Between T2 and T3 which were more or less comparable, the cows fed on the diet T3 had a higher digestibility for NDF, ADF and crude fibre, indicating that T3 was better than T2. These results suggest that complete rations with 25 to 35 per cent NDF, containing paddy straw as the sole source of roughage NDF, with the rest of NDF being met from non-forage sources, can be recommended for use among early and mid lactation dairy cows, with 35 per cent being the ideal NDF level.