Bulls are primarily used for breeding within the Muffin’s Milkers system. Breeding gives:
So bulls are quite sought after by cows wanting to produce a lot of milk.
Bulls also produce seed which is milked on the same milkers as cows.
Bulls are registered the same way cows are through the terminal system. They have their own levels as well.
A bull can also be a cow and a cow can also be a bull. A bull that is a cow can have their seed milked and do normal milking at the same time as long as they are wearing the appropriate gear.