Earlier quoted context omitted.
Pigs are omnivorous and naturally eat carcasses of other pigs or in the case of packs of wild boar, sometimes even kill other pigs to eat them. Feeding pigs with food containing bits of pig meat (like human food leftovers) is not ideal but it's not a very serious situation. Cows, on the other hand, are herbivores. Their digestive system cannot properly handle animal protein and this can have disastrous consequences.…
BSE has nothing to do with a digestive system that can't handle animal protein. After all, the human digestive system handles animal protein just great, but we can catch BSE by eating contaminated food even so.
Humans can get BSE (or Creutzfeldt–Jakob disease) from eating contaminated meat, but the meat gets contaminated in the first place because cows or other animals eat protein that they can't handle and produce misfolded proteins called a prions.