Neilsen and Spooner of Michigan State did a post hoc study of research looking at changes in bone as a result of either nutrition or exercise. The interest in decreasing skeletal injury in horses is of course of great practical importance to horse owners and trainers. They found that it is exercise that causes improvements in bone throughout the literature.
The studies of dietary treatments reviewed generally failed to elicit responses in bone metabolism or markers of bone quality in horses (finding high variability and low repeatability). Nutrients evaluated increased and varying concentrations of Vitamin D, dietary protein, calcium, lysine and threonine, phosphorus, trace minerals, supplemental manganese, and inorganic mineral supplementation. Although many of the nutrients were found to increase growth rates they did not elicit changes in the bone. Even when looking at results from the other way low starch concentrates fed in sufficient amounts to reduce growth rate in yearlings did not have an effect on bone minerals deposition.
All the exercise studies reviewed, except one involving lunging only, showed improvement in bone quality markers with exercise. Interestingly, the two studies comparing stabled to pastured horses showed a decrease in bone quality with the stalled horses. The bone quality changed quickly as the load requirements changed for the horses.
Their conclusion from looking at the research was that, “The horse appears capable of altering its absorption of nutrients to maintain bone health to a much greater degree than its ability to maintain bone strength if not provided with adequate exercise”.
Small changes in exercise, not nutrition, often result in measurable changes in bone
Comparative Exercise Physiology 2008, 5(1); 15–20
BD Nielsen* and HS Spooner
Department of Animal Science, Michigan State University, East Lansing, MI 48824, USA
* Corresponding author: email@example.com
Skeletal injuries in the equine athlete are a tremendous concern with both economic and animal welfare implications. As a result, much research has focused on improving bone quality through nutritional and exercise interventions. With the recent utilization of biochemical markers, changes in bone metabolism can be monitored. This study examined and compared the response of bone markers and estimates of bone mineral content, in studies with nutritional interventions, with those utilizing exercise interventions. The post hoc analyses suggest that nutritional interventions result in less change to bone markers and bone mineral content than exercise treatments. Of the bone markers examined, osteocalcin correlates most strongly to estimates of bone quality while keratin sulphate, an indicator of cartilage turnover, showed the least correlation. Comparing the results of this study with other published studies, similar findings were observed, suggesting that small alterations in exercise play a greater role in affecting measurable changes in bone metabolism and quality of the equine athlete than do small changes in nutrition.