The suffering of sentient creatures (ostensibly somewhat tautologous, since sentience entails the capacity to suffer) in their billions the world over.
As you've said, but by your actions you are complicit in it.
You are giving animals the capacity to have feelings and concerns they do not have.
The cow does not worry that it is on a farm and might one day be killed for food.
It does not think at all, apart from eating grass.
They are animals, that are not humans. They are food.
Given that, and the fact they CAN feel pain, I would like them to be converted to food, painlessly.