The Connection Between Moldy Hay and Heaves

The Connection Between Moldy Hay and Heaves

Hay produced this year might have been put up with a higher degree of moisture concentration and, therefore, is at risk of becoming moldy.

Photo: Alexandra Beckstett, The Horse Managing Editor

Horse owners know you can’t underestimate the power of being prepared. As such, most of us start to stock our winter hay supply in the summer, which is also the time when producers are harvesting and putting up new hay.

According to the National Weather Service, Central Kentucky experienced higher-than-average rainfall in the early summer months of 2015 (especially in April, May, and June). While that amount of rain, combined with warm spring and summer temperatures, allowed for green pastures, it also posed a significant challenge for hay producers.

Much of the hay produced this year might have been put up with a higher degree of moisture concentration and, therefore, is at risk of becoming moldy. Never feed moldy hay to horses, as it can cause several respiratory problems, the most important of which is heaves. Heaves is a chronic performance-affecting respiratory disease in horses that begins as an allergic reaction to eating moldy hay and breathing in other organic particulates.

We suggest that you pay close attention to your hay and dispose of any moldy bales you find. While it might too late to test your summer-purchased hay for moisture content, you can invest in a hay moisture tester for future hay purchases, so you never again have to buy hay that was bailed too wet.

The following University of Kentucky publication provides more information about heaves: http://www2.ca.uky.edu/agc/pubs/asc/asc172/asc172.pdf.

Fernanda C. Camargo, DVM, PhD, associate professor and equine Extension specialist in the University of Kentucky College of Agriculture, Food and Environment’s Department of Animal and Food Sciences, provided this information.


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