Credit: Amy K. Dragoo
In my role as an independent equine nutritionist, I work with a lot of dressage athletes. For the most part, these horses are fairly straightforward in terms of their nutritional needs. However, there are three common problems that I have observed: insufficient trace minerals, inadequate vitamin E and a lack of quality protein.
Many dressage horses are relatively easy keepers, able to maintain their desired body weight with little more than quality hay. As a result, owners often feed minimal amounts of fortified commercial feeds. As these horses are used for competitive goals, the products selected tend to be performance feeds. On the surface this appears to make sense. However, these feeds typically have serving sizes upward of 6 pounds per day. When fed at one scoop per day (many 3-quart scoops hold no more than about 3 pounds of these feeds), inadequate levels of vital trace minerals and vitamins are consumed. The horse’s condition may be perfect and his coat may be good because adequate calories and protein are being consumed, however, trace-mineral deficiencies may exist. Commonly, copper and zinc are the minerals most affected. Copper is necessary for the formation of collagen, which is the foundation of bone, ligaments and tendons. Zinc is involved in more than 300 processes in the body and is an important component in immune-system function and hoof health. Both play roles in skin health and coat condition and color. Over time, sub-optimal intakes of these nutrients may have detrimental effects on your horse’s health. If you are feeding a commercially fortified feed at intakes lower than the manufacturer’s recommended levels, your horse’s diet may be deficient in these key minerals and potentially may also be unbalanced. When the balance between various minerals is outside of ideal ranges, even in the face of adequate intakes of each mineral, absorption may be impacted and deficiencies may still exist.
Vitamin E is necessary to reduce oxidative stress and cellular damage caused by working muscles, which generate free radicals, the by-products of the oxidative processes occurring within cells. Free radicals are molecules with an unstable electrical charge. In an attempt to become stable, they steal electrons from other molecules, setting up a chain reaction that can result in damage to cell components. Antioxidants, such as vitamin E, bind to free radicals or inhibit them in some way, helping to stop the damaging chain reaction. Insuring adequate quantities of antioxidants helps to reduce oxidative stress and the associated cellular damage. Vitamin E is present in large quantities in good-quality fresh pasture, however, it is not heat-stable, and levels in hay are low. Although included in most commercial feeds, the amount consumed by your horse may or may not be adequate to meet his needs. This is because not only are there different types of vitamin E with different levels of absorption (natural d-alpha tocopherol is better absorbed than synthetic dl-alpha tocopherol), but utilization once absorbed varies from horse to horse. Signs of inadequate vitamin E supply include muscle soreness, stiffness and slower-than-expected recovery after work. Additionally, some horses appear to have a hard time building adequate muscling for the level of work they are doing. Given the individual variability in vitamin E utilization, I recommend having your veterinarian take a blood sample and test the level of vitamin E and selenium (another important antioxidant) and then supplement as necessary based on the results.
Another cause of difficulty building adequate muscle and improving an under-developed topline in dressage horses is inadequate quality protein. While the majority of diets provide more than adequate levels of crude protein, the quality may not insure the necessary essential amino acids. Protein quality is determined by the proportion of essential amino acids making up that protein. These are amino acids that must be present in the diet because the horse is unable to make them himself. Often horses in need of a better-quality protein source are in good weight but look skinny along their toplines. Owners sometimes believe that their horses are underweight, but feeding more calories would likely result in the horse becoming obese. The issue may not be a lack of calories, but rather a lack of quality protein. Under developed necks, a lack of muscling along the back under the saddle area and an angular rump may indicate a need for a better-quality protein source. Many commercial feeds include essential amino acids, however, if being fed at less than the required daily intake, this can leave the diet short.
All of these deficiencies are easy to remedy through the careful reading of feed tags, correct choice of feeds and the targeted use of supplements. Removing these deficiencies from your horse’s diet will help insure that his feeding regimen is providing everything he needs so he can handle his workload and reach his full athletic potential.
Clair Thunes, PhD, graduated from the University of California, Davis, in 2005. Born and raised in England, she is an independent equine nutritionist and owner of Summit Equine Nutrition LLC, an equine nutrition consulting company based in Sacramento, California, that works with horses of all types and levels.