Baldurs Gate has a Speak with Animals spell. If you use it, it becomes clear that animals have intelligence, they have their own opinions, feelings, dreams. This is already a double reason to fight against animal abuse.
Can we eat intelligent beings?
How then will our hero be different from the goblins who roast the dwarf at the stake?
The game has already implemented a vegetarianism system: in order to replenish health, the player has the freedom of choice: he can eat meat, or he can eat fruits and drink health potions. So everyone can answer this question on their own
But is it possible to do a quest to rescue the bulls from the tiefling camp in order for them to find freedom? And escape the terrible fate of being eaten.
Posts like this are why we need more content, people are losing rational thought through boredom.
However I am bored enough to answer: The second you let a domestic animal lose in a non civilised world something will eat it.
That's why adventurers carry all those weapons. To stop from being eaten.