The bull is the emblem of the moral principle, and the cow is the representative of the earth. When the bull and the cow are in a joyful mood, it is to be understood that the people of the world are also in a joyful mood. The reason is that the bull helps production of grains in the agricultural field, and the cow delivers milk, the miracle of aggregate food values. The human society, therefore, maintains these two important animals very carefully so that they can wander everywhere in cheerfulness. But at the present moment in this age of Kali both the bull and the cow are now being slaughtered and eaten up as foodstuff by a class of men who do not know the brahminical culture. The bull and the cow can be protected for the good of all human society simply by the spreading of brahminical culture as the topmost perfection of all cultural affairs. By advancement of such culture, the morale of society is properly maintained, and so peace and prosperity are also attained without extraneous effort. When brahminical culture deteriorates, the cow and bull are mistreated, and the resultant actions are prominent by the following symptoms.
(SRIMAD BHAGAVATAM-------1:16:18-------PURPORT).

The principal sign of the age of Kali is that lower-caste śūdras, i.e., men without brahminical culture and spiritual initiation, will be dressed like administrators or kings, and the principal business of such non-kṣatriya rulers will be to kill the innocent animals, especially the cows and the bulls, who shall be unprotected by their masters, the bona fide vaiśyas, the mercantile community. In the Bhagavad-gītā (18.44), it is said that the vaiśyas are meant to deal in agriculture, cow protection and trade. In the age of Kali, the degraded vaiśyas, the mercantile men, are engaged in supplying cows to slaughterhouses. The kṣatriyas are meant to protect the citizens of the state, whereas the vaiśyas are meant to protect the cows and bulls and utilize them to produce grains and milk. The cow is meant to deliver milk, and the bull is meant to produce grains. But in the age of Kali, the śūdra class of men are in the posts of administrators, and the cows and bulls, or the mothers and the fathers, unprotected by the vaiśyas, are subjected to the slaughterhouses organized by the śūdra administrators.
(SRIMAD BHAGAVATAM-------1:17:1-------PURPORT).

As He grew to six and seven years old, the Lord was given charge of looking after the cows and bulls in the grazing grounds. He was the son of a well-to-do landholder who owned hundreds and thousands of cows, and according to Vedic economics, one is considered to be a rich man by the strength of his store of grains and cows. With only these two things, cows and grain, humanity can solve its eating problem. Human society needs only sufficient grain and sufficient cows to solve its economic problems. All other things but these two are artificial necessities created by man to kill his valuable life at the human level and waste his time in things which are not needed. Lord Kṛṣṇa, as the teacher of human society, personally showed by His acts that the mercantile community, or the vaiśyas, should herd cows and bulls and thus give protection to the valuable animals. According to smṛti 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. It is mentioned herein that the beautiful cows and bulls were of various checkered colors—red, black, green, yellow, ash, etc. And because of their colors and healthy smiling features, the atmosphere was enlivening.
(SRIMAD BHAGAVATAM-------3:2:29-------PURPORT).

The cow is the most important animal for developing the human body to perfection. The body can be maintained by any kind of foodstuff, but cow's milk is particularly essential for developing the finer tissues of the human brain so that one can understand the intricacies of transcendental knowledge. A civilized man is expected to live on foodstuffs comprising fruits, vegetables, grains, sugar and milk. The bull helps in the agricultural process of producing grain, etc., and thus in one sense the bull is the father of humankind, whereas the cow is the mother, for she supplies milk to human society. A civilized man is therefore expected to give all protection to the bulls and cows.
(SRIMAD BHAGAVATAM-------3:5:7-------PURPORT).

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