Effect of replacement of berseem (Trifolium alexandrinum L.) hay by berseem silage on performance of growing rabbits

摘要

Two experiments were done to study the effect of partial replacement of berseem hay by berseem silage on the performance of growing rabbits. In the first one, 8 mature eight-months-old male NZW rabbits with an average body weight of 2.5 kg were used to determine digestibility coefficients and nutritive values of berseem hay (BH) and berseem silage (BS). In the second one, 30 NZW growing rabbits of 60 days of age were used in a complete randomized design experiment with three treatments. The first group was fed commercial rabbit diet including 40% BH (control diet), while in the other two groups 50 or 100% of BH was replaced by BS throughout the 70 days of the experiment. Results of the first experiment indicated that the contents of crude protein (CP) and ash tended to be higher, but the contents of organic matter (OM), crude fiber (CF), ether extract (EE) and nitrogen free extract (NFE) tended to be lower in BS compared with BH. The digestibility coefficients of DM, OM, CP, CF and NFE and the contents of TDN, DCP and DE were significantly higher (P<0.05) for BS than BH. In the second experiment, the contents of CP and ash tended to increase, but the contents of OM, CF and NFE tended to be decreased with increasing the level of replacing BH by BS. The digestibilities of DM, OM CP, EE and NFE and TDN, DCP and DE values and caecal values (TVFA's and NH3-N concentrations) increased significantly (P<0.05), however pH value decreased significantly (P<0.05) with increasing the level of replacing BH by BS. The final body weight, total and daily weight gain, the total and net revenue and net revenue improvement increased significantly (P<0.05), however, the average daily and total DM intake, the amount of DM required per kg weight gain and also the feed cost and feed cost/kg gain decreased significantly (P<0.05) with increasing the level of replacing BH by BS. The slaughter weight, carcass weight, dressing percentage, meat weight and percentage increased significantly (P<0.05), but the DM content of the meat decreased significantly (P<0.05) with increasing the level of replacing BH by BS. Protein content in meat of rabbits fed 50 and 100% BS diets was significantly higher (P<0.05) than that of those fed commercial diet, while the contents of ether extract and ash were nearly similar for different groups