OSTEOCHONDRITIS-DISSECANS IN AN APPALOOSA FOAL ASSOCIATED WITH ZINC TOXICOSIS

This report describes a severe case of osteochondritis dissecans (OCD) in a 5-month-old foal raised on a drylot contaminated with mine taili ngs. The high levels of zinc found in the liver from the foal at necro psy suggest that zinc toxicity contributed to the development of the O CD, as previously described. However, extensive efforts to determine t he source of the excess zinc in the foal's environment were unsuccessf ul since the feed, water, and soil all contained normal levels of zinc .