Theoretically, cows will be in estrus again after 280 days of pregnancy, and calves 720 will be fertile after 30 days of birth. Theoretically, seven cows can give birth to 42 calves after five years of artificial insemination, and the first seven cows can give birth to eight cows and 50 cows. Of course, if the first child is all female, you can have six more children, a total of 56 children.

But in fact, the success rate of breeding and the survival rate of cattle are less than 65,438+0,000%. Seven cows have bred 30 cows in five years. 1 head Niu Yi eats about 3,500 yuan of grass feed every year, which is about 3,500 kilograms of grass or 1.500 kilograms of coarse feed such as hay and straw. Plus labor, site, water and electricity, medicine, etc. The burden of not selling at all is heavy.