In Sri Lanka our family had a small farm with only one cow for milking purposes.
We milk the cow only in the morning and left the calf with the mother cow till evening.
We sold excess milk but used all the money just to buy the food for the cow.
We consume too much dairy products in western countries causing allergy reactions.
Too much pesticides are used for animal farming.
Now I consume soy products instead of cow milk.
It is not practical for a Buddhist monk to not to accept milk products as Dana.
By products of cows are found every ware. (shoes etc)
I think best thing is to live with one meal a day like a Buddhist monk.