Most form pairs during the breeding season, but in some species, such as fur seals, the gray seal (Halichoerus grypus), and elephant seals, males (bulls) take possession of harems of cows and drive rival bulls away from their territory.
Look for the crooked tail. This is probably the best ways to tell if a cow has been bred: A cow or heifer will have a crooked tail or a tail that is held out in an odd angle than usual for 24 to 48 hours after being serviced by the bull. 1  4 Edit step.
Cows that have been bred within 24 hours will have a bit of a kink in their tail. Also, waiting at least 21 days after breeding season or after the suspected time she has been settled to see if that cow goes back into heat is another good way of telling of a cow has been bred or not.