You can find answers with a google search on both of them. But if you want it from my belief system, cow's milk was designed for calves. Goat's milk was designed for baby goats. I believe I have read a dozen reasons why goats milk is superior to cows milk for humans. Goats milk is supposed to be more similar to human milk. I try to stay away from milk for the most part. I don't worry about calcium deficiency. I get my calcium from supplements and green vegetables and fruit. Cows get their calcium from grass. Cow's milk has the protein casein in it. Do a google search on casein. You will find information on casein that is negative for humans. Goat's milk doesn't contain casein.