季节对内蒙古地区犊牛成活率和日增重的影响

Effect of Season on Survival Rate and Growth Performance of Calves in Inner Mongolian Dairy Farms

为研究牧区季节因素对犊牛初生重、成活率和日增重的影响,本试验从内蒙古地区32个奶牛场收集了11.2万次产犊记录、5.5万头母犊牛的实际生产数据,整理、分析得到该地区犊牛初生重、成活率和日增重的季节性变化规律。结果表明:1)温暖月份(5、6月份)犊牛初生重最高,寒冷月份(12、1、2月份)犊牛初生重最低(P<0.05);2)寒冷月份(1、2月份)的接产成活率显著低于其他月份(P<0.05);3)11、12月份犊牛哺乳期发病率显著高于410月份(P<0.05);2月份发病成活率显著低于310月份(P<0.05);4)710月份日增重显著高于12月份到次年4月份(P<0.05)。综合上述结果,冷应激对犊牛的影响大于热应激,犊牛冷应激的临界温度为10℃。

To study the influence of seasonal factors on the birth weight of calves, the daily gain,approximately 55000 healthy calves were collected from32 dairy farms from July of 2014 to June of 2016 in Inner Mongolia. The results show that： （1） the highest birth weight of calves were born in warm season （May, June）, the lowest birth weight of calves in cold season （Dec. toFeb. ） （P〈0. 05） ; （2） The survival rate of January and February was significantly lower than that in other months（P 〈0. 05） ; （3）In November and December, calves＇ morbidity was signilicantly higher than that in Aprll to October （ P 〈0. 05） , the morbidity and survival rate in February were remarkably lower than that from March to Octo-ber （P〈0. 05） ; （4）The average daily gain from July to October was signilicantly higher than that from De-cember to the following year in Aprll （P〈0. 05）. Basedon the above results, it is concluded that the effect of cold stress on calves was more signilicant than heat stress; the critistresswas10 ℃ .