“According to smrti regulation, the cow is the mother and the bull the father of the human being. The cow is the mother because just as one sucks the breast of one’s mother, human society takes cow’s milk.
“Similarly, the bull is the father of human society because the father earns for the children just as the bull tills the ground to produce food grains. Human society will kill its spirit of life by killing the father and the mother.”
Srimad Bhagvatam 3.2.29