A study from Belgium suggests that feeding practices alone may aid the healing of minor developmental bone lesions in young horses.

Researchers at the Equine Research Center of Mont-le-Soie tracked 204 foals enrolled in a routine screening program for orthopedic disease. Each youngster was radiographed twice: once at 6 months old and again at 18 months old. At the beginning of the study, each horse’s caretaker completed a questionnaire about management practices, including housing and feeding routines.

At the first screening, 132 foals had no detectable bone troubles and 72 had signs of osteochondrosis (OCD), a growth-related disruption of the conversion of cartilage to bone in joints. OCD leads to swelling and lameness and, if unaddressed, can result in long-term soundness problems. When the second set of radiographs was taken 12 months later, 132 horses still had healthy bones, but the number of those with OCD lesions dropped to 37. None of the study horses had surgical intervention to address OCD between screenings.

After the second screening, the researchers correlated the radiographs with information gathered through the questionnaires. They discovered that foals who had lesions at the first screening were more likely to have normal radiographs 12 months later if they were not fed concentrates during the intervening period. “When we talk about concentrates, we mean every grain or processed grain,” says Luis Mendoza, DVM. “Most of them were commercial foal’s food with added nutrients. These have a high energy content compared to hay.”

Earlier studies show that genetics, combined with high-energy diets, can make young horses susceptible to OCD. “Our previous and parallel studies identified an overexpression of several genes in the OCD-affected population,” says Mendoza. “Some of these genes are related to bone formation but also to energy metabolism. High-energy diets would block the ex-pression of some metabolic pathways related to the bone formation.”

He notes, however, that the period when OCD can be influenced with diet is probably brief. “We can say that the effect is limited by age since definitive status for OCD is given around the age of 18 months. At that age, we consider that OCD lesions will not change any more,” says Mendoza. “Consequently, there is less likelihood of healing OCD lesions the closer we get to 2 years old.”

Mendoza encourages owners to carefully consider the necessity of concentrates in a young horse’s diet. “We cannot say that the concentrates themselves are negative for the osteoarticular status of the foals,” he says. “It is the excess of these concentrates that would alter energy metabolism, and subsequently bone metabolism. When the foal receives a good-quality hay or roughage, we recommend to reduce the concentrates since they might not be necessary.”

Reference: “Impact of feeding and housing on the development of osteochondrosis in foals—a longitudinal study,” Preventive Veterinary Medicine, May 2016

This article first appeared in EQUUS issue #469, October 2016.