holstein dairy cow

In this study, 60 Holstein dairy cow at the same age, birth order and lactation length were randomly divided into three groups. And there was no difference among three groups in milkyield.
本试验采取随机分组,将60头年龄、胎次、泌乳期相同,体重和泌乳量接近的澳系荷斯坦奶牛随机分成三组,各组间产奶量差异不显著。