Please be assured that the pilots know whether they have livestock in the hold and it's their job to know. Lossely speaking (category wise) they know what they are carrying and plan accordingly. I don't want to sound patronising but the flight crew aren't clueless about what they are carrying down below.
And as awful as it sounds, the crew on your previous flights probably didn't tell the Captain anyway.... knowing what i've told you rather than not caring.
So please be reassured.
From crew of a different airline.