Well, I’ll agree with you there, that’s why hogs are so loaded with parasites, they lay in the own crap all day long, and it’s full of worms, pinworms, strongyloides, roundworms and just a whole host of things.
Ever give your cattle Fenbendazole, Praziquantal, Menbendazole, Albendazole?
I breed my own stock, and most of these can cause miscarriages, so you avoid these generally.
I do typically run a pretty broad spectrum of flukicides and the like for new cattle I’ve purchased and intend to integrate into the herd -— a bull, for example.
You nail them with whatever the vet deems prudent, then keep them in a seperate pasture for a couple of months until it’s breeding time. (You do this as a quaranteen, but also because you want to introduce a new bull when love is in the air.)