Exercise and Bone Development

Beneath the smooth surface of articular cartilage, subchondral bone gives structural support to joints. Normally, newborn foals have a lot of water in this layer, which is slowly replaced by calcium and collagen as the foal weights his joints. Research has shown that abnormalities in subchondral bone precede abnormalities in articular cartilage. Therefore, healthy subchondral bone is critical to joint soundness. The question remains as to the effect of exercise on optimal development of subchondral bone. For this reason, a study from Utrecht University in the Netherlands was conducted to evaluate the effects of withholding exercise on subchondral bone development in foals.

Week-old Dutch warmblood foals were put into two groups: One living in box stalls for five months, and the other turned out 24 hours a day. After five months, some foals were euthanized and their fetlock joints examined. The results showed that confining foals significantly decreased calcium deposition, collagen development, and collagen cross-linking, which is critical to collagen strength. In comparison, pastured foals had normally developing subchondral bone.

When the other foals were allowed to stay at pasture until 11 months of age, the only significant change in the fetlock was a further decrease in water content in the subchondral layer, which suggests that critical development occurs prior to five months. Pasture exercise appears to be quite suitable for physical loading of joints to stimulate normal subchondral bone development.

Brama, P.A.J.; TeKoppele, J.M.; Bank, R.A.; et al. Equine Veterinary Journal, 34(2), 143-149, 2002.

About the Author

Susan Piscopo, DVM, PhD

Susan Piscopo, DVM, PhD, is a free-lance writer in the biomedical sciences. She practiced veterinary medicine in North Carolina before accepting a fellowship to pursue a PhD in physiology at North Carolina State University. She lives in northern New Jersey with her husband and two sons.

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