乳牛

You cannot sell the cow and sup the milk.

不能既想卖乳,又想喝奶。

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

分别免疫泌乳期和妊娠乳，收集免疫乳。

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.

只因牦在偏远地区，养畜牦牧民又甚少与界接触，知识水平都普遍低下，以致牦价值不及羊和乳般广为人知。