Supplements are not always necessary to complement a healthy horse’s diet, according to equine veterinarians and nutrition specialists. However, when a balanced diet isn’t possible, supplements can help stave off mineral deficiencies.
A good grass pasture is best, followed by hay and grain, experts say. Hay makes up 50 to 100 percent of a healthy equine’s diet, serving as a source of energy, protein, vitamins, minerals and the fiber necessary for normal equine gastrointestinal function.
Supplements help balance any deficiencies of pasture, hay and grain in an individual animal.
“Virtually all commercial grain mixes are supplemented,” says Eleanor M. Kellon, VMD, owner of Equine Nutritional Solutions in Robesonia, Pa. “When diets are not correctly supplemented and balanced, common problems include skin and hoof issues, which then have owners looking for a supplement to correct that.”
The nutritional value of hay varies widely. Hay can be measured by its qualitative and quantitative characteristics, which may include a visual exam and chemical measures of nutrients and other components that influence nutrient levels and digestibility.
“Most owners do not understand complete and balanced nutrition,” says Stewart “Chip” Beckett, DVM, a senior veterinarian at Beckett & Associates in Glastonbury, Conn., an equine and large animal veterinary practice. “It is a good thing to engage owners in that conversation so we can help the horse be healthier. There is a lot of hype in supplement marketing, and it is hard to sort out the kernels of truth.”
Basic equine nutrition isn’t complicated, experts say.
“Salt, water and good, quality forage—pasture, hay, hay cubes—are needed for most, contrary to popular opinion,” says Sarah Ralston, VMD, Ph.D., Dipl. ACVN.
“Sometimes a single concentrate formulated for the specific stage of life and perhaps some vitamin/electrolyte supplements might be needed in highly stressed, hard-working performance horses,” says Dr. Ralston, an associate professor in the Department of Animal Sciences at Rutgers University in New Brunswick, N.J. “Older animals do not digest food as well, so the intake should change. A supplement may be required, like corn oil to increase calories, or feed a high fat grain product.”
Some supplement companies are good at matching what is in the bottle with the label, while some are not, Dr. Beckett says.
“Supplements are pretty laxly regulated, so the assurance that you get from pharmaceutical drugs is not present in oral supplements,” Beckett says. “There are big differences in various formulations, such as whether they are chelated or not, are they part of a structure, or is it raw mineral that may or may not be absorbable by the gut?”
Feed and water should be tested before supplements are used, authorities say. They also advise that using too many supplements is a waste of money and is of no benefit to the horse.
“People often waste a good deal of money on supplements when the issues could be addressed by diet analysis and providing only the nutrients they need,” Dr. Kellon says.
Basic maintenance needs are about 2 percent of body weight daily from dry matter. So a 1,000-pound horse doing little or no work needs 20 to 30 pounds of hay or grain a day. The more work they do, the more food they need. The accepted formula is 2.5 percent of body weight for horses that do light to medium work and 3-plus percent for heavy workers.
Kellon notes that the total amount required drops according to how much grain is fed, because grains are two to three times more calorie dense than hays.
“Lactating mares and growing horses will be in the upper range and adult idle horses and mares in late gestation will be in the lower end of the range,” says Laurie Lawrence, Ph.D., a professor of equine nutrition at the University of Kentucky in Lexington, Ky. “For horses in the lower range, most of the diet will consist of forage.”
Pasture often needs only trace mineral balancing, Kellon adds. In addition, hay needs vitamin E and flax. If old or faded, hay also needs vitamin A.
Whom to Trust
Basing diets on scientific evidence is the best route for effectiveness, experts say. Veterinarians should discuss diet with owners and not rely on manufacturers to take the lead, they add.
Equine nutritionists say they often find that owners will ask other owners, their trainer or their farrier for diet recommendations before asking a veterinarian. Kellon says equine veterinarians looking to provide clients with more information need to evaluate supplements by understanding the science behind the issue being addressed.
With so many manufacturers professing their product to be the best, little regulation and a lack of a universal nutrition authority, knowing how to make the right dietary recommendations may be as challenging as getting the owners to listen.
“I strongly suggest keeping up with the most recent controlled research by getting the proceedings from the Equine Science Society meetings and Equine Science centers,” Ralston says. “Regional deficits are documented—Florida and Washington state are notoriously deficient in selenium—and in those cases most reputable feed companies supplement their concentrates accordingly.
“But this can really backfire, too,” Ralston continues. “The Rocky Mountain region is known to have alkaline soils high in selenium and calcium, but irrigation of hay fields can leach the minerals out.”
When Supplements Are Needed
Developmental bone diseases in young horses have a nutritional component, experts say. Even a simple salt deficiency can cause anything from poor performance to impaction.
“A wide variety of immune system imbalances and weaknesses have nutritional components,” Kellon says. “Skin and hoof problems are often nutritional. Whatever efficacious supplement form the horse will accept will work. My old mare will not touch feed ‘contaminated’ with a powder, in her opinion, but accepts liquids or pills hidden in treats.”