This will effect any Minecraft world. Create a survival world, then go into "Open to LAN", and change the world to creative. Then, get a horse spawn egg and a stack of golden carrots. Switch back to survival and use the egg to create a horse. You can keep feeding the horse carrots, even after love mode, the stack will just dissapear if you hold down right click whilst aimed at the horse.

This continues even after exiting and re-entering the world.