Effect of pre-weaning feeding regimens on post-weaning growth performance of Sahiwal calves.

摘要

The objective of the study was to assess the post-weaning growth response of Sahiwal calves reared on four different pre-weaning dietary regimens. The four diets were: (a) whole cow's milk, starter ration (SR; CP=20%, total digestible nutrients (TDN)=72%) and Berseem hay (H; Egyptian clover; CP=21%, TDN=63%); (b) whole cow's milk+H; (c) milk replacer (MR; reconstituted to supplier specification; SprayfoReg.)+SR+H; and (d) MR+H. The protein and fat percentages of reconstituted MR were 2.22 and 1.84, respectively. Milk or MR were fed at the rate of 10% of the calves' body weight (BW) until 56 days of age, and then withdrawn gradually until weaned completely by 84 days of age. The average initial BW of calves in groups A, B, C and D were 56.3+or-1.0, 47.5+or-1.0, 40.4+or-1.0 and 30.3+or-1.0 kg, respectively. Initially, there were 12 calves in each group with six of each sex; however, one male calf died from each of groups B and C and were not replaced. During the post-weaning period, 13 to 24 weeks, the calves were fed a single total mixed ration ad libitum based on maize, canola meal, wheat straw and molasses containing 16% CP and 70% TDN. Daily feed intake and weekly BW gains were recorded. The data were analyzed by MIXED model analysis procedures using the statistical program SAS. The intake of calves as percent of their BW, feed conversion ratio and cost per kg of BW gain were not different (P