Equine JOCC Project Conclusions Revealed

Equine JOCC Project Conclusions Revealed

The major conclusions from the project relate to causes, risks, genetics, management, and performance. But ultimately researchers confirmed what some have thought all along: JOCC might be one disease, but it’s a very complex disease.

Photo: Anne M. Eberhardt/The Horse

Researchers have a better understanding of equine osteochondrosis and juvenile osteochondral conditions (JOCCs) now that a major project on the disorders has concluded and its results have been published in the Veterinary Journal.

JOCCs are lesions in young horses' growing joints and bones that appear in various sites and have multiple causes, including genetics, nutrition, and external forces (such as pressure from exercise or injury). But because of the varying lesion sites, types, and causes, JOCCs are very complex and historically have been challenging for veterinarians and researchers to fully comprehend.

To combat that challenge, European equine orthopedic researchers teamed up to create a unique, multifaceted research program focused entirely on JOCCs. Members of the “Breeding, Osteochondral Status, and Athletic Career (BOSAC)” program investigated the growing skeletons of nearly 400 horses on more than 20 major breeding farms representing Thoroughbred racehorses, Standardbred trotting racehorses, and Warmblood riding horses in their standard breeding environments. Jean-Marie Denoix, DVM, PhD, Dipl. ACVSMR, director of the Centre d'Imagerie et de Recherche sur les Affections Locomotrices Equines in Normandy, France, initiated and headed the program. Paul René van Weeren, DVM, PhD, Dipl. ECVS, professor in the department of equine sciences at Utrecht University in the Netherlands, co-authored the study conclusions.

“The big merit of this study is that it was a field study,” van Weeren told The Horse. “This has forcibly led to restrictions and (some) loss of accuracy, but it reflects well the situation in the field.”

The Horse has been closely following the results of the BOSAC study, which has given new insight into numerous aspects of JOCCs, including:

The BOSAC researchers have also reviewed and refined the terminology used for these conditions specific to young horse musculoskeletal systems, and they’ve developed a reliable and more accurate scoring system to describe the individual lesions' severity. This progress was made possible thanks to an advanced understanding of how the disease develops and how different kinds of lesions relate to each other, van Weeren said.

The major conclusions from the BOSAC study relate to causes, risks, genetics, management, and performance. But what they have confirmed is what some researchers have thought all along: JOCCs might be one disease, but it’s a very complex disease.

“Joints react differently, and even sites within joints are not always comparable,” van Weeren said. “This is very well exemplified by the genetic studies where so many linkages are found with so many different genes and chromosomes.

“This means we'll never have a simple panel of a few genetic markers with which we can eradicate the problem, and we also may not expect the same effect for every joint of breeding and selection policies that are chosen.”

Van Weeren confirmed that environment—the way horses are managed and raised and the kinds of exercise and injuries they experience—plays an important role in JOCC development. One thing they have learned for certain is that environment's effect is inherently linked to the horse's age.

“This is very coherent with what is known about age-related changes in the development of the equine musculoskeletal system,” van Weeren said. “But again, this doesn’t make things any simpler.”

The research project's conclusion, "The Normandy field study on juvenile osteochondral conditions: Conclusions regarding the influence of genetics, environmental conditions and management, and the effect on performance," appeared in July in the Veterinary Journal

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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