产犊季节、胎次及牛场对荷斯坦牛泌乳性能的影响

本研究收集了3个千头以上奶牛场共8872条相关信息，采用多因素方差分析法分析了不同产犊季节、胎次和牛场对泌乳天数、305d校正奶量、305d脂肪产量、305d蛋白产量和全泌乳期产奶量5个泌乳性能指标的影响。结果表明，不同产犊季节、胎次和牛场都极显著影响奶牛的该5项泌乳性能（P〈0．01）。夏季和秋季产犊奶牛的泌乳性能较为理想。夏季产犊奶牛的泌乳天数和全泌乳期产奶量最高，其他三个泌乳性能指标都位居第二；秋季产犊奶牛的305d校正奶量、脂肪产量和蛋白产量都显著高于其他三个季节（P〈0．05），泌乳天数和全泌乳期产奶量也仅次于夏季。头胎牛的各项泌乳性能都显著高于其他胎次的奶牛（P〈0．05），其次为2胎产犊奶牛。随着胎次的增加，泌乳性能的各项指标都有不同程度的降低。不同的牛场极显著地影响奶牛的泌乳性能（P〈0．01）。

The Influence of Different Calving Seasons, Parity and Farm on Milking Performances of Holstein

The influence of different calving seasons, parity and farm on reproductive performances were analyzed by multiple factor variance analysis based on 8 872 records from 3 dairy farms feeding more than one thousand dairy cattle. The five reproductive performances index contained lactating days, 305-days milk yield, 305-days fat and protein yield, and the whole lactation milk yield. The results showed that effect of different calving seasons, parity and farm on milking performances of Holstein was highly significant （P〈0.01）. The milking performances of calving cows in summer and autumn were more ideal. Lactating days and the whole lactation milk yield of cows were the highest in summer, and the other three lactation performances were in second place. 305-days milk yield, 305-days fat and protein yield in autumn were significantly higher than the other three seasons （P〈0.05）. Lactating days and the whole lactation milk yield in autumn were only after summer. The milking performances of first lactation cows were significantly higher than the others parities （P〈0.05）, followed by the second lactation cows. The five milking performances reduced in different degree with the parities increased. Different farms had highly significant effects on milking performances of Holstein（P〈0.01）.