Untamed horses, lamas, mules and donkeys can be endlessly fed

Summary:
Untamed horses, lamas, mules and donkeys can be endlessly fed.

Steps to reproduce:

1. Summon the horse, mule, llama or donkey.
2. Take the food that these animals eat.
3. Feed animals with food (endlessly).

Observed results:
You can feed animals with food until you get tired.

Expected results:
Untamed mobs will have a limit of tameability, after which you cannot feed untamed mobs.