Well, we don’t see many cows in herds with intact males and fertile females. And if we did, I’m pretty sure there would be a lot of mating going on when a cow is in estrus.
The most necessary things for animals to do is procreate. This is why they eat, why they try to maintain or advance their pack status, and why they avoid being eaten. Passing on their genetic material is, by definition, what makes a species successful.
