While holding Zombie flesh Tamed wolves display button Sit or Stand instead of Feed.
Wolves don't display Sit or Stand buttons unless you're holding something
Dogs (tamed wolves) cannot be healed to full health
Wolf feed button acts like sit and stand on client
Fish button makes your pet sit/stand when retrieving fishing bobber
No feed button for Mooshrooms, Chickens, Pigs, Sheeps, Rabbits and Tamed Wolfs