10 Things You Might Not Know About Equine Nutrition

Equine nutrition is complex and it is easy to become overwhelmed when choosing what to feed your horse. We collaborated with Dr. Clair Thunes of Summit Equine Nutrition to share ten things you might not know about equine nutrition.

1. Feed by weight, not volume. It is tempting to feed by flakes or scoops, but feedstuffs have different densities and weights. A flake of alfalfa does not weigh the same as a flake of grass hay, and a scoop of sweet feed does not weigh the same as one of oats. Weigh the concentrate initially and mark the scoop for consistency. Weigh a flake from the bale and adjust as needed. Repeat anytime you change feed.
2. There are pros and cons to alfalfa. Love it or hate it, alfalfa is highly palatable, a good protein source, and easily digestible. It is higher in calories than other forages, so it may not be a good choice for easy keepers. Protein and calcium levels can also be excessive. High alfalfa diets are linked to gastric stones (enteroliths), which can cause colic. When fed, alfalfa should be 25 to 30% of the daily forage, and no more than 50%.
3. Balance forage diets with a ration balancer. Ration balancers provide amino acids, vitamins, and minerals that may be deficient in forage. These nutrients are supplied without added calories in the form of fat, starch or sugar, which is important for horses that need diets low in non-structural carbohydrates (NSCs). Research has also shown that fortification of trace minerals may prevent developmental orthopedic disorders in young horses.
4. Feed according to the label or add a ration balancer. When horses are fed below the recommended amount of grain for their type as listed on the label, the amount of vitamins and trace minerals in the diet will likely be insufficient. This can result in deficiencies that need to be corrected by a ration balancer.
5. Environmental factors affect the nutritional content of forage. Where forage is grown, variations in rainfall, mineral content of soil, the growth stage at harvest, the amount of leaves versus stems and how it is stored influence the nutritional content. Sugar levels in pasture grasses vary by season, maturity, and time of day. Have forage tested and work with a veterinarian and/or nutritionist to analyze the results.
6. Horses without regular access to fresh green grass should have their vitamin E levels tested. Vitamin E, an antioxidant that protects against cell damage, boosts immune system response, and prevents debilitating neuromuscular diseases, is abundant for horses with access to lush green pastures. Not all horses exhibit clinical signs of vitamin E deficiency, but unless horses are on green pasture for at least 6 months/year, they require supplementation. Test your horse’s blood vitamin E levels and discuss the results with your veterinarian before adding vitamin E supplements.
7. Horses can have mineral deficiencies despite access to a salt block. Voluntary sodium intake from salt blocks varies between horses, potentially falling short of maintenance requirements. To ensure that your horse’s sodium needs are met, give 1 tablespoon of loose salt per 500 pounds of body weight in feed, along with access to a salt block. Although mineral blocks may contain trace minerals such as zinc and copper, they are probably not consumed at significant levels. A ration balancer should be added to ensure trace mineral needs are met.
8. Supplements are largely unregulated. The U.S. Food and Drug Administration categorizes most animal feed ingredients as “generally recognized as safe”. As long as no unsubstantiated claims are made about curing or treating disease, safety and efficacy testing is not required. Many supplement companies employ good manufacturing practices, but it is up to the consumer to verify that this is occurring. Importantly, ingredients found in supplements can potentially alter pharmacologic effects of medications. Additionally, exercise caution when combining supplements as unknown mineral concentrations can potentially exceed recommended dietary mineral intake levels.
9. Horses with endocrine disorders require veterinary input on feed as grain and pasture can lead to laminitis. Studies have established connections between obesity, insulin resistance, EMS and cases of laminitis. The best way to prevent laminitis in horses with endocrine disorders is with diet and exercise. Limit NSCs, including fructose, glucose, lactose, sucrose, and starch, in the diet, especially in horses that are unable to exercise due to their condition. Grains and grasses are often high in NSCs, which can lead to laminitis in at-risk horses. Work closely with a veterinarian or equine nutritionist to ensure proper dietary management of diagnosed horses.
10. If a horse is offered water with electrolytes, also provide fresh water. Horses lose electrolytes (chloride, potassium, and sodium) when their bodies sweat to cool down. This can cause an electrolyte imbalance and affect muscle function. Electrolyte supplements can support recovery after prolonged or strenuous exercise. However, horses must consume water to gain the maximum benefit from supplemented electrolytes and avoid dehydration. Ensure that your horse has access to plain, fresh water to encourage appropriate water intake.