The next symptom of the age of Kali [the present age] is the distressed condition of the cow. Milking the cow means drawing the principles of religion in a liquid form. The great rishis and munis [sages] would live only on milk. Srila Shukadeva Gosvami would go to a householder while he was milking a cow, and he would simply take a little quantity of it for subsistence. Even fifty years ago, no one would deprive a sadhu of a quart or two of milk, and every householder would give milk like water. For a Sanatanist (a follower of Vedic principles) it is the duty of every householder to have cows and bulls as household paraphernalia, not only for drinking milk, but also for deriving religious principles. The Sanatanist worships cows on religious principles and respects brahmanas [topmost class, the "heads" of society responsible for maintaining religious principles]. The cow's milk is required for the sacrificial fire, and by performing sacrifices the householder can be happy. The cow's calf not only is beautiful to look at, but also gives satisfaction to the cow, and so she delivers as much milk as possible. But in the Kali-yuga, the calves are separated from the cows as early as possible for purposes which may not be mentioned in these pages of Srimad-Bhagavatam. The cow stands with tears in her eyes, the shudra milkman draws milk from the cow artificially, and when there is no milk the cow is sent to be slaughtered. These greatly sinful acts are responsible for all the troubles in present society. People do not know what they are doing in the name of economic development. The influence of Kali will keep them in the darkness of ignorance. Despite all endeavors for peace and prosperity, they must try to see the cows and the bulls happy in all respects. Foolish people do not know how one earns happiness by making the cows and bulls happy, but it is a fact by the law of nature. Let us take it from the authority of Srimad-Bhagavatam and adopt the principles for the total happiness of humanity.
...An ordinary man may possess an ordinary cow, give protection to this animal, take sufficient milk from it, and engage the milk to produce butter and clarified ghee, especially for performing the agnihotra-yajña. This is possible for everyone. Thus we find that in Bhagavad-gita Lord Krishna advises go-rakshya, the protection of cows. This is essential because if cows are cared for properly they will surely supply sufficient milk. We have practical experience in America that in our various ISKCON farms we are giving proper protection to the cows and receiving more than enough milk. In other farms the cows do not deliver as much milk as in our farms; because our cows know very well that we are not going to kill them, they are happy, and they give ample milk. Therefore this instruction given by Lord Krishna—go-rakshya—is extremely meaningful. The whole world must learn from Krishna how to live happily without scarcity simply by producing food grains (annad bhavanti bhutani [Bhagavad-gita 3.14]) and giving protection to the cows (go-rakshya). Krishi-go-rakshya-vanijyam vaishya-karma svabhavajam [Bg. 18.44]. Those who belong to the third level of human society, namely the mercantile people, must keep land for producing food grains and giving protection to cows. This is the injunction of Bhagavad-gita. In the matter of protecting the cows, the meat-eaters will protest, but in answer to them we may say that since Krishna gives stress to cow protection, those who are inclined to eat meat may eat the flesh of unimportant animals like hogs, dogs, goats and sheep, but they should not touch the life of the cows, for this is destructive to the spiritual advancement of human society.