Nevermind. I retract that. I see that riding horses regularly get corn now as long as its balanced with oats and not too processed.
I know that any significant volume was frowned upon at one time for draft animals.
“too hot, not enough protien, a handful is good for their teeth” is what they used to say.
I was just thinking about what these animals eat in the wild. Horses like various herbs off the ground such as fennel and others, and if let loose in a cornfield they are happy too. They like carrots.
Cows in the wild just graze. Grass, alfalfa, whatever they can forage but they don’t eat corn off the stalk.