乳牛

You cannot sell the cow and sup the milk.

不能既想卖,又想喝奶。

Its safety and efficacy were tested and used to immunize the lactational and gestational bovines.

分别疫泌期妊娠，疫。

Only because yak is living in remote area and oxherd, with low knowledge,  has less communication with outside world , the yak is less heard and popular as sheep and milk cow.

只因牦栖息在偏远地区，养畜牦的牧民又甚少与界接触，知识水平都普遍低下，以致牦的经济价值不及羊般广为人知。