Choosing Horse Supplements: a Miracle in a Bottle

Select supplements based on your horse’s individual needs.

Many horse owners use supplements to gain a competitive edge or to help their horse feel better. Some supplements have been shown to benefit equine health and well-being; however other products labeled as "supplements" by unscrupulous manufacturers have not gone through a governmental testing process proving their efficacy. Know what to watch for to help you, and your horse, get a lot more out of your supplement choices.

Seeking To Understand

In both her education and career, Kathleen Crandell, PhD, a staff member at Kentucky Equine Research (KER), an equine nutrition research and consulting company based near Lexington, Ky., has studied the effects of nutritive supplementation on equines, ranging from performance horses to broodmares.

"People are usually looking for a miracle in a bottle; they often expect the supplement to do more than it can," cautions Crandell. One common supplement many horse owners are familiar with is fat in the form of corn or soy oil, but she says we've come a long way in understanding what it can do and what's best for the horse.

"You can look at fat from corn or soy oil as a basic energy supplement or a source of extra calories, but we now understand a great deal more about the composition of fats and what are the right kinds for horses," Crandell says. It's not just the right kinds of fats, but how they're balanced in the diet that's important. "You have to consider the essential fatty acid composition and how that's going to affect the body; you want to have omega-3 and omega-6 oils, but in the correct balance, since they each have different cellular actions."

More Is Not Necessarily Better

Equine nutrition is a fairly young yet complex field. Combine that with research leading to frequent changes in information, understanding, and long-held horse management habits, and getting current data about supplements into the hands of those that administer them can be a challenge. One example is the mindset that a supplement "couldn't hurt, might help."

"Sometimes we'll see a horse being fed multiple supplements, maybe because a neighbor or a family member recommended it," notes Crandell. "There are some supplements where more is not a problem, but some can be given to the point where toxicity develops."

For example, she points to dietary iodine as a potential "red flag" supplement; it's a nutrient the thyroid needs for proper production of hormones that can't be produced by the body, so it must be consumed in the diet. Adequate amounts are usually supplied in forages, commercial grain concentrates, and iodized salts provided in a salt block. However, Crandell has noticed a recent trend to supplement iodine instead of the more expensive thyroid replacement drug for horses with sluggish thyroids, and she notes that caution should be used with this practice. "Iodine can be consumed to the point where it becomes toxic for the horse," says Crandell. "If you're not reading labels or don't fully understand what's okay, or how supplements work together and the overall effect in the diet, there's a potential for harm."

However, she believes knowledge about supplementation is improving. "I think people are getting a lot smarter about supplements and how they work and taking the time to read labels and directions and understand the interactions between different products," she says.

Truth in Labeling

Bill Bookout is constantly on the lookout for harmful supplements. As president of the National Animal Supplement Council (NASC), Bookout is responsible for monitoring the monthly data entered into the NASC Adverse Event Reporting System, which helps the organization maintain vigilant watch over more than 5,000 different products.

"People don't realize that a specific classification for dietary supplements doesn't exist for animals the way it does for people," says Bookout. "There's also a difference in the way the government recognizes a general vitamin supplement used for overall animal health, which is considered a food, and a product that's aimed at supporting a specific bodily function, which might be considered a drug," says Bookout.

Technically, a joint supplement falls under the drug category for horses, but there are possible avenues around collecting the data required for drug approval when bringing a product such as this to market.

"In the case of joint supplements, you can't patent a natural supplement formula, and there's no way equine supplement companies could spend $5 million on testing," he explains. "It would raise costs to the point they couldn't compete financially in the marketplace. The Food and Drug Administration, or FDA, understands this, so they can allow products to be marketed under 'enforcement discretions,' provided companies act responsibly."

What this means is that while a joint health supplement is technically an unapproved drug, if the company acts responsibly by monitoring the product, not making claims about treatment for specific medical conditions, and has a quality control protocol in place, that company might be allowed to market and sell its joint supplement. The exception is with injectable drugs. "Injectable drugs should always be approved by the FDA," advises Bookout.

When you're evaluating a company and its products, how can you tell what's what? Bookout says there are a few key things any horse owner can look for (see sidebar).

"Claims that are too good to be true usually are," he cautions. Any company making a claim regarding a specific disease or body part should be suspect. He also says while the Internet is a good tool for consumer research, information should be taken with a grain of salt.

"Ronald Reagan said 'trust, but verify.' That's what consumers need to do to find the best option for their animals," he says. "Never hesitate to pick up the phone and ask questions of the company. And, it's always a good idea to have a veterinarian or equine nutritionist involved; opinions vary on supplementation, but if it's important to you, find one that will work with you and your horse."

Minimum Daily Requirements

Equine nutrition is a complex topic (see's Nutrition/Supplements topic page for more detailed nutrition information), but there are some basics to keep in mind when it comes to what supplements horses might need and when. Instances where supplementation might be beneficial to your horse include when vitamins or minerals are missing or lacking from the diet; to exert an anti-inflammatory effect; or to provide antioxidant effects.

"Forage is essential for horses," says Crandell. "Grass is generally better than hay, because once you cut and dry the grass you start losing some of the nutrients, especially vitamins." Forage alone is unlikely to provide adequate nutrition for any horse other than a nonworking, "pasture ornament" equine.

"Forage might provide enough calories, or maybe enough protein for the average backyard horse, but when you get down to trace minerals, such as zinc, copper, manganese, and selenium, it could be marginal compared to what it was 100 years ago," she adds. "Selenium in particular is very low in certain areas of the country. However, vitamin A should be sufficient if the grass or hay is green, and vitamin E should also be fine with fresh grass." You can send a hay or pasture sample to a lab for analysis to reveal the nutrient levels that are low in your area of the country, or the vitamins/minerals your horse's forage lacks that he requires.

Once you add activity into the equation, Crandell says a horse's daily requirements go up. "A working horse or one under stress from competition or travel needs more of everything; more energy, more protein, and more vitamins and minerals," she notes.

Too Much or Too Little

Most commercial feeds are designed to be fed in five- to 10-pound rations per day, and Crandell reports going beneath that threshold could mean a horse isn't getting enough feed for his basic health requirements, in terms of vitamins and minerals. In those scenarios, she says, the horse might need one or more supplements added to his diet. "All the nutrients are included in the appropriate ratios at that level," she says. "If you have a horse that's only eating a few handfuls of feed, such as an obese horse or one that's insulin-resistant, he is probably not getting enough to balance what's missing from his forage."

However, simply increasing feed or grain rations isn't the answer, either. "A high grain diet results in a lot of grain going into the hindgut, where it is fermented, producing lactic acid and dropping the pH," points out Crandell. That starts a chain reaction, affecting everything from digestion to physical appearance.

"A low pH in the hindgut can result in what we call hindgut acidosis; basically, it's an acidic environment that interferes with the microbes needed for digestion. Without those microbes, horses don't feel well and will often have an unhealthy coat," she says.

Take-Home Message

Horses are as individual as humans when it comes to their dietary needs, and owners should select and administer supplements with care. Consider your horse's career, health status, and life stage when evaluating his diet and any potential supplementation; also know where your horse's feed comes from and what's potentially missing from the soil in terms of nutrients. And finally, assess supplement products carefully, based on factual and reliable information. Your horse's health and well-being depend upon it.

About the Author

Lisa Kemp

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