Researchers Study Horn Fly Resistance in Organic Holstein Dairy Cattle

Researchers at Penn State University who have been studying horn fly resistance in dairy cattle report that Holsteins with predominately white coats had lower fly loads than those that were predominately black. The researchers were looking for heritable resistance to provide organic producers with more options for horn fly control. Horn flies not only cause painful bites, but can lead to decreased milk production and poor animal health. Researchers aren’t yet suggesting breeding for whiter cattle, however: they can be prone to sunburn and eye cancers. Also, the cattle with the least horn fly resistance were the ones that produced the most milk.