摘要 : The study was taken up to assess the effect of strategic supplementation of bypass fat (BPF) on the performance of high yielding crossbred cows. Crossbred cows (15) in early lactation, producing more than 10 kg milk/d were used. B... 展开 The study was taken up to assess the effect of strategic supplementation of bypass fat (BPF) on the performance of high yielding crossbred cows. Crossbred cows (15) in early lactation, producing more than 10 kg milk/d were used. Based on the body weight, milk yield, stage of lactation and parity, the animals were divided into 2 equal groups. The animals in the control group (C) were offered <i>ad lib.</i> homemade concentrate mixture and non-leguminous green fodder for 180 days. The animals in the experimental group were offered <i>ad lib.</i> control diet, supplemented daily with 150-200 g BPF i.e. calcium salts of rice bran fatty acid oil. The BPF supplementation did not have any significant impact on blood profile except an increase in triglyceride (TG) level. The plasma progesterone concentration was higher on day 15 of the observed oestrus cycle (7.50 vs 6.15 ng/dl) as well as at 30 days of pregnancy (9.18 vs. 6.93 ng/dl) in BPF supplemented group as compared to control group. Concentration of blood urea nitrogen (BUN), TG and phosphorus declined, while that of albumin and calcium increased with the advancement in lactation. The average daily milk yield was improved by 1.13 kg/d (21.55 vs. 20.42 kg/d) in BPF supplemented group as compared to control group with an increase in protein, lactose and SNF content in milk, without effecting milk fat content as compared to control group. The advancement in the stage of lactation did not have any significant effect on these parameters. Supplementation of BPF showed no effect on milk urea nitrogen (MUN), but it declined with the advancement in the stage of lactation. The body weight of the animals was improved considerably in BPF group as compared to control (551 vs. 508 kg) group, but was not affected by stage of lactation. It was concluded that supplementation of 150-200 g bypass fat/d improved the milk yield, its composition and health of the crossbred cows. 收起