My pig research has borne fruit:
"It is not uncommon to find blood in a pen and around the mouths of pigs but with no obvious prolapse in any other animals, i.e. the prolapse will have been completely chewed off."
And then there is this...
CASE REPORTS
Pig Bite of Prolapsed Rectum in a Child
By A.N. Gangopadhyay, D.K. Gupta, Amit Dhulkotia, Ashwin V. Apte, and S.P. Sharma
Varanasi, India
STRAY PIGS are a menace in rural areas of poor countries in which pig rearing is a common occupation. However, pig bites to humans are rare, and a bite to the perineum has not been reported. A very unusual incident in which a pig bit a prolapsed rectum while the child was defecating is being reported.
