Osteochondrosis in horses

First results of osteochondrosis study in Dutch warmblood horses.

The first results of an important joint research project the prevalence and heritability of osteochondrosis (OC) are now available. The participants in the project, which began in 2005, are the Animal Breeding and Genomic Centre (ABGC) and the Dutch warmblood studbook KWPN.

In this study, 800 offspring of 32 representative stallions were scored using radiology for OC in the stifle joint, the hock joint and both the hind and front fetlock joints. On average, 25 yearlings from each stallion were used. The first results have shown that a genetic component is responsible for the development of OC.

A complete genetic study will now be performed to investigate the differences in genetic background between joints and differences between factors influencing the development of OC. This study will continue for two more years.

Osteochondrosis (OC) is currently the most prevalent developmental disorder in horses. OC develops in young growing animals, such as horses, dogs, pigs, cattle, and poultry, and can even occur in human children. During growth, a disturbance occurs in the process of ossification, resulting in the formation of abnormalities in the bone and cartilage. These abnormalities can be detected on radiographs, on which diagnosis is based.

At present, OC affects approximately 30% of young horses worldwide, mostly in warmblood breeds. Of the 12,000 foals born each year and registered by the Dutch warmblood studbook KWPN, an average of 3,000 will develop OC during their first year.

In the results from this study, the genetic component that is responsible for the development of OC was shown by the large differences between offspring groups of stallions. An equally high frequency of OC was observed in the left and right limbs.

Regarding specific joints, the prevalence of OC was lowest in the hock joint, medium in the fetlock joints and highest in the stifle joint. It was found that sedation increased the accuracy of radiographs and thereby the accuracy of the diagnosis, especially in the stifle joint.