Abstract:According to the current situation of dairy cow and beef cattle industry and the characteristics of Holstein male calves,the fattening experiment of male calves was carried out to realize the coordinated development of milk and meat.A total of 86 dairy male calves aged 12-13 months,14-15 months,16-17 months and 18-19 months were selected for fattening tests to determine feed intake,daily gain and slaughter performance.The results showed that after 45 days of fattening,the daily weight gain of calves aged 16-17 month old was up to 1.69 kg/d,which was 36.3%,22.46% and 19.86% higher than that of calves aged 12-13 month old,14-15 month old and 18-19 month old,respectively.Within the range of normal dietary nutrition level,increasing dietary nutrition level and extending fusing time could moderately improve the slaughter rate and net meat rate,but the improvement range was not significant.The slaughter rate and net meat rate of experimental group with average body weight of 567.97 kg were the highest,reaching 56.78% and 46.02%.According to the analysis of experimental data,the daily gain of dairy male calves increased slowly after fattening at 18 months of age,which decreased compared with 16-17 months of age.At the same time,the feeding cost continued to increase,and the daily profit margin narrowed.The results of this experiment showed that when the male calves were fattened to more than 500 kg at 18 months of age,it was the most suitable for the breeding.
