Once a mom, always a mom.
Mothers have the truly amazing ability to step in and nurture, even when it's a totally different species. When Treasure the boxer was introduced to eight orphaned piglets, she stepped up to the plate as their surrogate mom.
Since Treasure was a stray, no one knows her background or if she previously had puppies. It seems like that might be the case, though, because once the pigs started suckling, Treasure produced milk.