DENVER (CBS4)– Denver Parks and Recreation has sold some bison calves to keep the remaining herd sustainable.

Twenty-five yearling bison calves from the city’s two famous herds off Interstate 70 were sold at auction. One of the calves sold for $2,500. The auction raised $48,000.

The money will be used to provide food and veterinary services for the remaining herd of nearly 60 animals.

Denver Parks and Rec maintains the herd to preserve bison which were nearly wiped out in the 1880s.