Farms with large acreage and many mares and foals are more likely to have cases of Rhodococcus equi foal pneumonia than smaller farms with fewer horses, according to a recently published Texas A&M University (TAMU) study. Additionally, farms that are intensively managed and use what are considered desirable practices to prevent disease are more likely to have R. equi cases.

R. equi is the most common cause of severe pneumonia in foals. Many breeding farms in Central Kentucky and other states are R. equi endemic, meaning the disease is present at a given farm on a recurrent basis. The study examined variables on 138 farms (65 affected and 73 unaffected) and appeared in the Feb. 1 issue of the Journal of the American Veterinary Medical Association.

Noah Cohen, VMD, PhD, Dipl. ACVIM, professor of equine medicine at TAMU’s College of Veterinary Medicine and lead author on the study, said the associations with farm size and numbers weren’t that surprising, but the health management factor is puzzling.

“Our current thinking is that it (the association of disease with intensivity of management) probably indicates that those practices, while desirable for other infectious diseases, are not adequate for resolving this problem,” he added