Blue Post on Pet feeding in combat from beta boards:
There are talents in all 3 pet trees that you can invest in if maintaining happiness is a problem (or just annoying) for you.
We're also trying to give you a few more options to keep your pet alive, such as more Avoidance and reduced spell damage, and even more ways to heal your pet. Of course you can always choose to focus directly on more damage and hope your pet survives long enough to make good use of it.
|
tl;dr version: you will never be able to feed your pet in combat.