Veganism Or Cow's Milk Consumption?
"According to Vedic life and according to all Vedic scriptures, a man should live on fruits and vegetables, for his teeth are made in such a way that these can be very easily eaten and digested. Although it is nature's law that one has to live by eating other living entities, one must use discretion... Milk, for example, is an animal product, the blood of an animal transformed, but the cow delivers more milk than is needed by her calf because milk is intended for man. Man should simply take the milk and let the cows live and thus following nature's law, man will be happy..."
Source: "Krsna Consciousness-The Matchless Gift" by His Divine Grace A.C.Bhaktivedanta Swami Prabhupada.