From Milk you can prepare hundreds of Preparation | Srila Prabhupada

But the cow protection is recommended because it has got the miracle food, milk, and from milk you can prepare hundreds of preparation, all nutritious, full of vitamin A and D. So therefore it is recommended, go-raksya (cow protection).

Room Conversation with Scientists
His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
July 2, 1974, Melbourne