This are cows not humans, my experience is with real world cows that are raised outside on fields,when the cow is in heat she will start ridding other cows(yes cows become lesbians and "rape" other cows, I know your mind is blown now), a bull will smell her from a distance and will come to the cow, the cow is always wiling because is her nature, she is not a thinking human it is all instinct.

At my grandparents farm artificial insemination was used when there was no old enough bull present(this is on small villages in Romania, and to make you even more outraged animals like horses are still used for work).