Horse Feeding Basics

A horse should consume at least half of his diet in forage (hay and pasture) and receive grain only if needed to meet his energy needs.

Photo: Anne M. Eberhardt/The Horse

 Learn how to properly craft your horse's diet

Providing a properly balanced equine diet is one of the most crucial parts of horse ownership, yet its complexity means it is frequently misunderstood or even overlooked. Whether you’re the only one who cares for your horse or you rely on boarding facility staff to help, you should have a basic understanding of proper horse feeding to be sure your horse is on an acceptable nutritional plane. If you need help developing a diet to meet your horse’s individual needs, your veterinarian, an equine nutritionist, and/or an extension specialist can be great resources.

For this article we’ve called on four equine nutritionists and extension specialists for their best feeding advice.

Evaluating Body Condition

The first step in crafting a horse’s diet, says Rhonda Hoffman, PhD, PAS, Dipl. ACAN, professor of horse science at Middle Tennessee State University, in Murfreesboro, is knowing whether he is healthy. “First, and most importantly, horse owners must be able to look at their horse and assess whether it is at a healthy weight or too fat or too thin,” she says. “The eye of the feeder fattens (or thins) the horse.”

Horse owners should acquaint themselves with the Henneke Body Condition scoring system that ranges from 1 (emaciated) to 9 (obese). The ideal body condition score is from 4 to 6.

“Five is ideal, and (these horses) should have moderate fat cover over the crest of the neck, behind the shoulders, over the ribs, and over the loin and tailhead,” says Carey Williams, PhD, associate professor and associate extension specialist at Rutgers, the State University of New Jersey, in New Brunswick. “Ribs should be easily felt but not seen. This will help the horse owner determine if the horse needs to gain or lose weight.” 

(For an illustrated description of each score on the Henneke scale, see TheHorse.com/30154.)

Understanding the Math 

Next, you will need to know how much your horse weighs to calculate how much to feed him and what. Unless you take your horse to a facility that has a large-enough scale, such as a veterinary clinic or commercial farm, you will need to calculate his estimated weight using a weight tape. The formula differs depending on whether a horse is a young growing horse, a pony or draft breed, lactating or pregnant, in heavy work, underweight, or overweight. However, the general calculation for the average light horse breed is: 

Body weight in pounds = (Heart girth in inches2 x Length in inches*) / 330

*Length of the horse is measured from the point of the shoulder blade to the point of the rump.

“A weight tape placed moderately tight (you should still be able to fit a few fingers under the tape) around the highest point of the withers around the girth area will give you a weight estimate plus or minus 50 pounds,” says Williams. Taking a measurement every two weeks should reflect any weight changes.

Bob Coleman, PhD, BSc, assistant professor and extension horse specialist at the University of Kentucky, in Lexington, suggests using technology to determine a horse’s weight. “There are a number of formulas, and more recently the University of Minnesota released an app called the ‘Healthy Horse,’” he said. “This allows horse owners a means to measure their horse and get an estimate of what it currently weighs and then an estimate of the horse’s ideal weight. That tells the owner where they are at and if the horse needs to gain, lose, or stay the same.”

Weight, along with age, amount of exercise, climate, body condition, reproductive status, type of horse (light horse, for example), etc., all affect a horse’s energy and nutrient requirements—the amount of calories, protein, fat, vitamins, and minerals he needs to consume. 

Start with Forage

Coleman and Williams suggest that horses consume 1.5-2.5% of their body weight daily in forage, with “easy keepers” on the lower end of that range (the “air ferns” of the horse world)  and “hard keepers” (those who have trouble keeping on weight) on the higher end. 

“Forage is the basis of all feeding programs, as this is a primary source of the basic nutrients needed,” Coleman explains. “Now, with that said, one can provide more than the horse needs, say with good pasture when a horse is at maintenance. The pasture intake is hard to limit unless you either restrict access to the pasture or use a grazing muzzle.”

 

So how do you know how much your horse is eating when he is out to pasture? Williams says a 1,000-pound horse in light work can consume 20 pounds of forage—grass and hay—per day. “You can assume that if they are out (to pasture) for eight hours, they will eat approximately one-third of their daily intake, so the remaining two-thirds of the day they are in the stall, they could eat the remaining, roughly 13-14 pounds.” 

Offer as much as possible of this remaining amount as other forms of forage, such as hay, and then only add grain if your horse needs it to meet his energy needs. 

Laurie Lawrence, PhD, professor in the Department of Animal Sciences at the University of Kentucky, says owners should remember that pastured horses are subject to dietary changes associated with pasture availability. Therefore, additional hay might be necessary if pasture quality declines.

If a horse is accustomed to always being on pasture, Hoffman says the owner will need to introduce any supplemental hay and/or grain into the diet gradually. The same is true for returning horses to pasture in the spring as well as in the fall after a frost: Do so gradually, as sugar levels in grasses increase during these times, which can, in turn, increase a horse’s colic or laminitis risk. In these situations, “start with a couple of hours at a time for two to three days, and then increase that by two hours every three days until the horse is out as long as you wish it to be,” Hoffman suggests. This also allows the microbial population in the horse’s gut that aids in food digestion to adjust to the pasture.

Feeding high-quality hay free-choice in addition to pasture could exceed some horses’ nutrient requirements, warns Coleman. He recommends owners learn about the nutrients that different forage types provide. For instance, a legume hay, such as alfalfa, is higher in calories, protein, and calcium than grass hay of a similar maturity. Grass hay usually provides all of the calories the “average” horse needs.

Hoffman suggests owners enlist their hay or feed dealer or local extension specialist to perform a nutrient analysis on their hay. “This $20-30 investment is small compared to the price of hay and feed, and it can help you better understand what sort of feed to buy to balance the nutrients in the hay,” she says. “If your hay is nutrient-rich, you can likely save money (by feeding) a less-expensive grain. As well, it is easier to justify a higher calorie, higher protein, more expensive grain concentrate if your hay is lower in nutrients.”

Horse owners all have their own hay preferences, but Coleman says his top choice is a mixed alfalfa-grass hay that meets many different horse classes’ requirements, from growing to performance to senior horses. Williams prefers a grass hay that meets the needs of a horse in maintenance, which includes 8-10% protein and adequate levels of vitamins and minerals. 

Regardless of your choice, know how much hay you’re feeding by weight, not volume, says Williams. Feeding hay by volume (e.g., two flakes per feeding) can result in inconsistencies, because flakes can weigh different amounts. Also inspect hay for brown, black, gray, or white spots, which are indicative of mold. Quality hay should be pale to medium green and not smell dusty, dank, or moldy, Hoffman says.

Does Your Horse Need Grain? 

As mentioned, if your horse is not getting all the nutrients he needs from forage, then you might need to add a concentrate feed to his diet. 

“Exercise increases the amount of calories a horse needs,” says Lawrence. “Growing horses have comparatively higher needs for calories, amino acids, minerals, and vitamins than most mature horses. Nutrient requirements also increase during gestation and lactation. Diets for pregnant and lactating mares must contain adequate nutrition or the mare will rob her own body stores to some extent to support fetal growth or milk production.”

Lawrence adds that good-quality commercial feeds usually contain adequate amounts of vitamins and minerals for the class of horse the label specifies. Again, feed by weight. 

“If you obtained a commercially manufactured sweet feed and looked closely, it will probably contain some pellets,” explains Lawrence. “In many cases these pellets contain the nutrient fortification in the diet, particularly in vitamins and minerals. This pelleted material is often referred to as a ‘balancer,’ because it is used to provide a balanced nutrient profile in the feed. Some feed companies sell this type of pellet alone and call it a ‘ration balancer.’ If a horse is getting all the calories he needs from forage alone, feeding a small amount of the ration balancer will ensure that he gets all of the minerals and vitamins as well.” Coleman recommends feeding one to two pounds daily if using a pelleted balancer, based on the horse’s body condition and nutrient needs.

As for the choice of grain, Hoffman suggests horse owners choose a commercially mixed and balanced grain concentrate rather than feeding basic grains, such as oats, or trying to mix your own feed to save a few bucks. Without a nutritionist’s help, chances are you’re going to end up with a feed that does not provide balanced nutrition or that your horse must eat more of to get enough nutrients.

“As a general rule where grain is concerned, you get what you pay for,” Lawrence adds, suggesting that you might have to purchase a mid-range to above-average priced feed to get the best balance between cost and quality ingredients and nutrients.

Horse rations should contain 1.6-1.8g of salt per kg of dry feed matter.

Water and Salt

Due to their size, horses must consume a large volume of water to keep their bodies functioning normally. A mature average-sized horse will drink 5 to 10 gallons per day. Of course, factors such as exercise, hot temperatures, humidity, sweating, pregnancy or nursing, and increased hay intake multiply the amount of water a horse needs, sometimes up to three or four times the normal amount. 

Make sure your horse always has free access to plenty of fresh water. Without enough water, impaction colic becomes a big risk, and an extended time without water can even result in kidney failure, brain damage, or organ shutdown. 

“Horses will typically drink two quarts (half a gallon) of water for every pound of hay they consume,” says Williams. 

Nutritionists also recommend that horse rations contain 1.6-1.8 grams of salt (sodium chloride) per kilogram of dry feed matter (what feed would weigh if all of the moisture were to be removed). Owners can provide additional salt through a mixture of one-third trace mineral or plain salt top-dressed on feed and two-thirds free-choice dicalcium phosphate (e.g., a salt block). This allows horses to meet their calcium and phosphorus needs as well, because these nutrients are not included in trace mineral salt blocks. 

Take-Home Message

If you are new to feeding horses, check with your veterinarian or an equine nutritionist to make sure his diet offers the nutrients he needs. Otherwise, he could develop serious health problems.

 

About the Author

Sarah Evers Conrad

Sarah Evers Conrad has a bachelor’s of arts in journalism and equine science from Western Kentucky University. As a lifelong horse lover and equestrian, Conrad started her career at The Horse: Your Guide to Equine Health Care magazine. She has also worked for the United States Equestrian Federation as the managing editor of Equestrian magazine and director of e-communications and served as content manager/travel writer for a Caribbean travel agency. When she isn’t freelancing, Conrad spends her free time enjoying her family, reading, practicing photography, traveling, crocheting, and being around animals in her Lexington, Kentucky, home.

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