Effect of Restricted and Ad. libitum Feeding during Late Pregnancy on the Performance of Crossbred Cows and Their Calves

The present research was undertaken to monitor the effects of restricted and ad. libitum feeding during last trimester of pregnancy on the performance of crossbred dairy cows and their calves. For this purpose two groups of crossbred cows having eight animals in each group were put into two plane of nutrition during their last three months of pregnancy. Dietary energy level in one group was calculated as per Ministry of Agriculture, Fisheries and Food, (MAFF, UK) and the cows on other group received ad. libitum feeding (concentrate level similar to MAFF, recommendation+ad. libitum roughage). After calving, the cows of both groups were given same diet (ad. libitum) to study the effect of feeding during pregnancy on subsequent lactation performance of the cows. It was observed that during pre-calving period cows on ad. libitum feeding gained significantly (p<0.05) more body weight than that of cows on restricted feeding ($38.50{\pm}6.04$ vs $21.37{\pm}8.04kg/cow$). There was no significant differences between the birth weight of calves of restricted ($21.31{\pm}2.18kg$) and ad. libitum ($20.31{\pm}3.27kg$) groups. Dietary energy intake of ad. libitum group ($50.22{\pm}4.24$ MJ ME/d/cow) was significantly higher (p<0.01) than that of restricted group ($39.76{\pm}1.03$ MJ ME/d/cow). During lactation period cows that were on restricted feeding produced little more milk (3.06 lit/cow/day), than that of the cows on ad. libitum feeding (2.84 lit/cow/day). Although growth rate of the calves of restricted group upto one month ($0.23{\pm}0.09kg/calf/d$) was significantly (p<0.01) higher than that of ad. libitum group ($0.17{\pm}0.08kg/calf/d$) but after four months the growth rate of the calves of two groups become nearly similar ($0.35{\pm}0.02$ vs $0.37{\pm}0.03kg/calf/d$) and difference between them was non-significant. During lactation period cows of restricted group gained little weight but cows of ad. libitum group lost significantly (p<0.05) more weight. Per day metabolizable energy intake in both group during lactation period was nearly similar (67.54 vs 69.58 MJ ME). It is concluded that ad. libitum feeding during last trimester of pregnancy is neither economic for getting maximum milk yield nor for calf growth rate and MAFF, recommended level of dietary energy during that period could be applied on our pregnant crossbred dairy cows.