Neonate losses are a significant problem for the equine industry. In one study in an equine-dense area, 68% of foal deaths occurred within the first month of life, with 41% occurring during the first week of life alone. Causes ranged from infections and musculoskeletal injuries to pneumonia and gastrointestinal disorders.

In the latest Horse Course video installment, Tracy Sturgill, DVM, PhD, and David Horohov, DVM, PhD, of the University of Kentucky's Gluck Equine Research Center, and Doug Byars, DVM, Dipl. ACVIM, of Byars Equine Advisory LLC in Georgetown, Ky., discussed the varied causes of foal mortality, current recommendations for preventing disease, and breaking research information on foal vaccination and immunity.

Sturgill described a study in which she examined the causes of foal deaths in Central Kentucky in 2004 and 2004. Septicemia--the presence of bacteria or bacterial toxins in the bloodstream--topped the list of causes of foal deaths, with Escherichia coli (E. coli) as the top single culprit causing this condition. Musculoskeletal injuries, pneumonia, and gastrointestinal disorders (including ulcers and colitis) followed septicemia as top causes of foal mortality.

"Infectious disease plays a major role in neonatal mortality," Sturgill said. "Prevention may be our best choice for decreasing the neonatal losses that we see."

Byars said there is little uniformity among equine practitioners on vaccinating horses, and he provided some background on different types of vaccines, the approval process for these products, and how horses respond immunologically to vaccination. He described current vaccination recommendations in the field based on endemic diseases in the area, available vaccines, and believed duration of immunity.

"Overvaccination is more common to equine practice than in veterinary practice in any other species," Byars said. Studies are under way to understand the immune system of the foal, with the goal of better facilitating protection against equine disease.


Horohov continued the presentation by discussing colostrum and foal immunity and how they impact foal vaccination practices. He also discussed maternal antibodies both as a protective and as an interference mechanism.

"Foals are immunocompetent when they're born," Horohov said, describing research in which he and Sturgill found that foals can produce antibodies in utero at eight months gestation. In a post-natal foal, they found foals "have the capabilities of responding, the problem ... is that their immune system is na�ve ... they have very few antibodies in the sera initially, at least those that are derived from the foal. Instead they rely upon mom, and the maternal antibodies pass through the colostrum to provide them with that first line of defense."

Horohov described several studies completed in his laboratory on vaccinating foals "in the face of maternal antibodies" (after the foals have received maternal antibodies from colostrum) and how different ages of foals respond to vaccination. He concluded with recommendations of when to vaccinate foals.

This year has partnered with the University of Kentucky's Livestock Disease Diagnostic Center and the Department of Veterinary Sciences to bring you the latest in equine research each month via online Horse Courses. Before this partnership began, the information was limited to those audience members who could attend the presentations in person.

"Unlike a typical research seminar that deals with an overly focused aspect of the problem, or a clinical presentation that emphasizes diagnosis and treatment, we combine each aspect into a singular presentation that in one hour's time highlights the most important aspects of the particular topic," said Horohov, William Robert Mills Chair in Equine Immunology and faculty member at the University of Kentucky's Maxwell H. Gluck Equine Research Center.

Horohov and Craig Carter, DVM, PhD, Dipl. ACVPM, director of the university's Livestock Disease Diagnostic Center, created the original seminar series and select the speakers for each seminar.

"Research findings are often unavailable for up to two years in the medical and lay literature," said Carter. "The Webcasts of the University of Kentucky Equine Diagnostic-Research Seminar series being offered by are just the ticket. Now, anyone in the world with Web access will be able to digest and use the content of these extremely high-quality seminars presented by some of the greatest minds in equine medicine and surgery."

Watch the Horse Course on foal disease, view other archived Horse Courses, and sign up for upcoming installments at

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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