单位代谢体重产奶量的非遗传因素分析

Analysis of Non-genetic Factors Influencing Milk Yield per Unit of Metabolic Body Weight

为了更客观地衡量奶牛泌乳性能,本研究分别对荷斯坦牛4%乳脂校正日奶量(FCM)、305d产奶量(305M)、单位代谢体重4%校正日奶量(FCM/MBW)和单位代谢体重305d产奶量(305M/MBW)进行了非遗传因素分析。于2014年和2015年收集了分别位于河南、北京两个地区的3个荷斯坦牛场685头泌乳牛的生产性能相关资料。使用SAS9.4软件的GLM过程,初步分析了场-年、胎次、泌乳阶段及其互作对上述指标的影响。结果显示,不同场-年305M差异极显著(P<0.01);305M与奶牛体重(BW)和体重二次项(BW2)有回归关系(回归系数分别为4.22、-4.23),但不显著(P>0.05);胎次对FCM/MBW及305M/MBW影响均不显著(P>0.05),且泌乳阶段也不影响305M/MBW(P>0.05)。本研究提出的FCM/MBW及305M/MBW能反映奶牛泌乳效率,且本研究结果显示305M/MBW只受场-年效应影响,因而这个指标用于衡量泌乳性能更客观。

To measure milk performance more objectively, we investigated the effect of non-genetic factors on fat cor-rected milk yield（FCM）,305-day milk yield, FCM per unit of metabolic body weight（FCM/MBW）and 305M per unit of metabolic body weight. Data of 685 cows were collected from 3 farms in Henan province and Beijing in 2014 and 2015. The effects of year-farm, parity, lactation stage and interaction effects among them on indexes mentioned above were analyzed by general linear model using SAS 9.4. Results showed that effect of year-farm on 305M were highly significant （P〈0.01）.The effect of BW and BW2 on 305M was not significant （regressive coefficient is 4.22,-4.23 respectively）. The effect of parity on FCM/MBW and 305M/MBW were not significant （P〉0.05）, so did the effect of lactation stage on 305M/MBW（P〉0.05）. The two indexes proposed from current study, namely FCM/MBW and 305M/MBW, can reflect the efficiency of milk performance, and our results showed that 305M/MBW was only affected by the year-farm effect, therefore these two indexes can be considered as objective measurements of milk yield.