两种算法推测奶牛产期准确性的比较

Comparison of Two Predictive Formulas for Calving Dates of Pregnant Cows

通过对奶牛两种推测奶牛产期算法准确性的比较,对两种算法的实用性进行了评价。选择辽宁省鞍山恒利奶牛场的30头妊娠母牛,记录其配种日期与实际产期,分别用两种算法对预产期进行估计,并与实际产期进行比较,分析两种算法的准确性。其中算法1为配种月减3,配种日加6;算法2为配种月减3,配种月为5月时配种日加4,为3月或4月时配种日加5,为7月或12月时配种日加6,其他配种月为配种日加7。结果显示,算法1和算法2预测的偏差差异不显著,实际生产中都可以使用;不同季节配种的奶牛,其妊娠期长短差异不显著;配准季节对两种算法的预测效果无显著影响。建议奶牛养殖中无论采用哪种预测算法,都应该在预产期前10d开始加强对孕牛的管理,并做好接产准备。

To investigate the application of two common formulas for prediction of calving dates,accuracy of predictions were compared.A total of 30 pregnant cows collected from Anshan Hengli Dairy Farm in Liaoning province,China were enrolled in this study.Predictive calving date was calculated for each cow using the two formulas,respectively,and then compared with actual calving dates.Formula 1 calculates the predictive calving date by subtracting 3 from the last inseminated month and adding 6 to the last inseminated day,while Formula 2calculates the predictive calving date by subtracting 3 from the last inseminated month and adding 4,5,6 or 7 to the last inseminated day depends on the last inseminated month is May,March or April,July,or rest of the month,respectively.Results indicted that season of insemination had no significant effects on gestation periods as well as the prediction accuracy of two formulas.And there were no statistically significant differences between the prediction errors of two formulas.Both of the formulas can be used for predicting calving dates.It is suggested that farm managers should take close care of pregnant cows and prepare for the delivery at least 10 days before the predictive calving date.