cow protection is essential_Srimad Bhagwatam

cow protection is essential. There is a miracle in milk, for it contains all the necessary vitamins to sustain human physiological conditions for higher achievements. (Srimad Bhagavatam 1.16.4 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)

…Milk is compared to nectar, which one can drink to become immortal. Of course, simply drinking milk will not make one immortal, but it can increase the duration of one’s life. In modern civilization, men do not think milk to be important, and therefore they do not live very long. Although in this age men can live up to one hundred years, their duration of life is reduced because they do not drink large quantities of milk. This is a sign of Kali-yuga. In Kali-yuga, instead of drinking milk, people prefer to slaughter an animal and eat its flesh. The Supreme Personality of Godhead, in His instructions of Bhagavad-gītā, advises go-rakṣya, which means cow protection. The cow should be protected, milk should be drawn from the cows, and this milk should be prepared in various ways. One should take ample milk, and thus one can prolong one’s life, develop his brain, execute devotional service, and ultimately attain the favor of the Supreme Personality of Godhead. (Srimad Bhagavatam 8.6.12 Purport)