MILWAUKEE (CBS 58) -- Nelson, a Norwegian fjord horse who lived at the Milwaukee County Zoo's Northwestern Mutual Family Farm since 2023, was humanely euthanized Friday morning, July 24, after a likely pelvis fracture, the zoo announced on social media.

He was nearly 18 years old and had recently been treated for pain in his left hip. His pain reportedly worsened in recent days, and he began having trouble with balance and walking, according to the zoo.

Thermal imaging showed the inflammation had spread quickly across his left hip and pelvis. Veterinary staff consulted with additional large animal veterinarians before making the decision.

Nelson shared the barn with Guiseppi, a miniature Sicilian donkey, who was given time with him following the procedure.

Zoo staff offered thoughts about Nelson and their memories in a social media post on Friday.