Veterinarians from the University of Minnesota's large animal hospital are hard at work treating several horses from two different farms.
One case involves 55 horses, ponies and donkeys saved from a Fillmore County property after the animals were found wounded and malnourished last week.
KSTP reports four of the animals were euthanized and 12 are being treated at the university's campus in St. Paul.
Criminal charges against the owner are possible, although none have been filed.
In Wright County, four horses are undergoing treatment after an outbreak of equine herpes. Veterinarians say another horse with the disease had to be put down.
Although humans cannot get the disease, equine herpes can spread through the air and is highly contagious among horses.