Cattle riding?
yeehaww
Well, I'm not sure, horses will really be the only ridable animals.
And currently i'm coding a breeding system for all animals, that would be able to turn, say, two couse into a loving island full of cows, this is what happened when I made a small system where when two cows "meet up", they make one or two cows, since there's absolutely no limitations of delays with this system, this happens.
It's horrific, but it's a proof of concept, really.
What I want to do is make a system where they have to go through a stage of "childhood" before they are able to reproduce with other cows, they are first babies, but when they hit adulthood, they make out with another cow, leading to the female cow getting pregnant, and after, say, a half or full day/night cycle, a baby is born! [And there's a chance that there would be another born, too.] the parent cows will no longer be fertile, and after a while, they just die.
I can't believe I wrote that, but this is a system that would let farmers breed their cows so they have more meat and milk to sell in the end, they'll probably have a very simple hunger system, too many cows on your farm? less grass, no grass? they starve to death, so you can't just pack a hundred cows into a small enclosure.
Most of the animals in the game will probably do this, not just cows.