Cows usually live about 20 years. Cows are mammals. 550,''says another guy. That is how people bid on cattle. There are lots of ways of bidding, that is just one way of bidding on cattle.
Cows have I.D. tags to claim their owner in bidding.
A cow can milk about 100 glasses of milk a day. Dairy farmers milk their cows every 12 hours. A cow can only give milk after she has a baby. Cows give about 200,000 glasses of milk in their lives. What a cow eats affects how much milk it gives.