Can putting foals on a controlled exercise program reduce the risk of fractures later in life?
Researchers at the University of Illinois at Urbana-Champaign (UIUC) are investigating.
Limb fractures risk ending not only a horse’s career but its life as well.
Led by Dr. Annette McCoy and Dr. Mariana Kersh, the research team are looking at the benefits of a carefully controlled exercise program in foals. The study is funded by the Morris Animal Foundation.
“We know from another study that mild exercise early in life is associated with positive effects in horses, but exactly how it stimulates bone growth in areas susceptible to fractures is still unknown,” says Dr. Annette McCoy, Associate Professor of Equine Surgery. “Exercise interventions earlier in their lives might better prepare a horse’s bones to face the mechanical forces they will see in their late adolescence and adulthood.”
The research draws on information from human medicine, where studies show that children who exercise are less prone to injury as adolescents and adults, and that bone changes are sustained over time.
In an earlier study, Dr. McCoy found that pasture-raised foals in their first year of life are relatively inactive about 85% of the time. The research group wondered whether this low level of voluntary exercise during the period of most rapid growth could contribute to bone injuries when horses are put into work as young adults.
The team also knew that too much exercise could have a detrimental effect on foals. Any exercise program should increase activity without over-stressing the foal.
The project, being conducted on the University of Illinois Horse Farm, is due to run over two years. The first six Standardbred foals were enrolled in 2021. A further six foals joined the study this year.
When each foal was 8 weeks old, the group performed baseline computed tomography (CT) exams on each foal’s forelimbs to create a three-dimensional picture. The exams measured bone properties, including density and volume.
Foals were then divided into two equal groups. Three foals participated in an 8-week exercise plan, consisting of 1,500 yards of fast trotting in a field once per day, five days per week. The other three foals served as non-exercised controls.
When each foal reached 16 weeks of age, the team performed another CT scan of their limbs to compare differences in bone development. When the foals are about 1 year old, the team will take one final CT scan to see if any changes remain after the conclusion of the program.
All the data will be combined into a computer model to help predict the effects of a variety of exercise interventions on bone properties without having to test them in live horses.
Although horses come in many shapes and sizes, Dr. McCoy hopes the results will help better manage foals of all breeds destined for activities where front leg fractures are common.
“Most foals, regardless of breed, spend the first year of their lives sleeping, standing and walking,” said Dr. McCoy. “Because we’re really focused on the pre-training period, I think that our findings should be applicable across breeds.”
“One of our goals with this project was to create a computer model that we could use in the future to virtually test exercise interventions in foals,” she said. “What one of our graduate students discovered is that the bones of foals react differently than adult horses to mechanical forces. This meant we couldn’t use the existing adult horse modelling systems for our study – we created something completely new. Nobody had demonstrated this before, and our student won the PhD competition at a recent meeting for this discovery!”
Dr. McCoy hopes to have all their data analyzed by the end of summer 2023.
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