not really an answer, but I read of a new Zealand farmer whose cow had mastitis. the vet was unable to find an anti biotic that worked and suggested putting her down. however, the farmer having read a creationist article about superbugs not being so super after all because they were highly specialized, decided to inject manured dirty water into the cow. the vet was furious but the mastitis cleared.   the theory being possibly that more common bacteria done the job. no definite claim is being made here. some days later it got mastitis again, and this time usual antibiotics worked. it was still alive at time of article.
is it possible that the donkey brushing against the cattle conferred something beneficial,,,i don't know...