You do your best to provide your horse with everything he needs for a healthy life, and sound nutrition is integral to those efforts. The three basic necessities--good grass and/or hay, salt and ample fresh water--are enough for many pleasure horses, but youngsters, broodmares, seniors and hard-working horses require the extra energy that grains and concentrated feeds provide.
When you purchase a ready-mixed feed, you rely on the manufacturer to formulate a nutritionally sound, high-quality ration. Yet choosing the right product for your horse requires more than just grabbing a bag of "senior feed" for an older horse, for example. It's also important to balance what's in the bag with the rest of your horse's diet--such as the quantity and type of forage he eats and any supplements he might receive--as well as his activity level, special health issues, etc.
It's not hard to find information that can help you make the best decision. Every bag of commercial feed includes a label that lists the ingredients and the nutritional value of the contents. But unlike the Nutrition Facts identified on human foods, the information included on animal feeds varies somewhat. Federal regulations set the basic standards, but each state can also establish its own guidelines for more specific reporting. Nonetheless, all labels ought to follow the same general format established by the Association of American Feed Control Officials (AAFCO).
Here's a look at the information you can expect to find on feed labels, how to interpret it, and how to use it to make the best choices for your horse.
Product Name, Purpose & Ingredients
The most basic information on any feedbag, after the product name, is the class of horses for which it is intended, such as lactating mares, growing foals, senior citizens or high-performance athletes. It's important to select the right type of feed for your horses so that you don't create imbalances or deficiencies. "Maintenance feed," for example, is formulated for the average mature horse in light work--it would not provide enough protein, calcium and other nutrients for growing foals.
Another important feature on the label is the ingredients list, which presents all of the constituents of a feed. The principal ingredients may be listed in one of two ways: by specific terms, such as rolled oats, rolled barley, soybean meal, etc., or by collective terms, such as "roughage products," which omit individual items within that category. Collective names are used to avoid having to reprint the label if ingredients change. For example, a feed that lists "roughage products" might contain varying amounts of barley hulls, dried beet pulp or peanut hulls, and "plant protein products" might include cottonseed meal, soybean meal or cultured yeast.
You are likely to find the greatest variation among products when you compare the guaranteed analysis section, which documents either percentages or quantities of various nutrients in a product.
Some manufacturers, for example, may include special ingredients, such as biotin or vitamin E, that are selling points for that particular blend. In addition, the Food and Drug Administration requires that the following basic nutrients be including on every feed label:
Crude protein:Proteins are chains of amino acids that support basic body functions such as muscle cell repair and the synthesis of enzymes and hormones. High levels of protein are especially important for young horses as they grow, as well as for broodmares and equine athletes.
As crucial as this nutrient is, however, I find that many horse owners place too much importance on the protein content of a feed, with little or no concern for other nutrients. A mature 1,200-pound horse in moderate work needs to consume about 1.5 to 1.75 pounds of protein each day to meet his needs. Crude protein ranges from 8 percent to 16 percent in most commercial horse feeds. To determine the amount of protein you are actually giving your horse, multiply the percentage crude protein by the number of pounds of the feed you offer. That is, 10 pounds of feed that is 14 percent protein contains 1.4 pounds of protein [10 pounds x 14 percent (.14) = 1.4 pounds].
When evaluating a horse's ration, remember that forage contains protein, too. Typical levels in grass hays range from 3 to 14 percent, and there is even more in alfalfa--at least 18 to as much as 25 percent. Most horses in light work will do just fine with a feed that supplies a lower amount of crude protein, especially if they are also receiving any amount of alfalfa hay in their diet.
Crude fat is one indicator of a feed's energy content. Fat provides nearly 2.5 times as much energy, pound per pound, than carbohydrates or protein--the higher the crude fat, the more calories the feed provides. Fats are burned as fuel, but they are also important to the diet as carriers for fat-soluble vitamins, and they form certain essential fatty acids, which aid many cellular functions.
I find that people tend to overlook the crude fat content, which can tell you how many pounds of feed a horse needs. If it's a higher energy feed, you need to offer a lot less to provide the same amount of calories.
Most grain-based feeds provide between 2 and 4 percent crude fat, but some formulated for energy contain as much as 14 percent. Horses digest fats more safely and efficiently than they do starch, and if an individual needs the extra calories, it's better to provide the same quantity of a higher fat feed than to simply increase his portion of starchy grains alone.
Crude fiber consists of the carbohydrates that are not digested or absorbed for use as fuel or to build body tissue. Horses are designed to be forage eaters, and a high-fiber diet is crucial for normal digestive tract function.
Indirectly, the crude fiber level on a feed tag is the single best indicator of energy content, even more so than crude fat. Fiber provides energy, but only at very low levels when compared to soluble (digestible) carbohydrates or fat. So as fiber content goes up, the energy content goes down. More specifically, the crude fiber percentage tells you how much of the feed consists of grains--which ranges from 2 percent for energy-dense grains such as corn to 12 to 14 percent for bulky grains such as oats--and how much consists of hays and other forage that are high in fiber.
Concentrate mixes containing less than 7 percent fiber are dense in energy and must be fed with great care to avoid overloading the horse with starches, which can lead to laminitis. Concentrates with 8 to 11 percent fiber are moderate in energy, while concentrates with greater than 12 percent fiber are low in energy. Feeds with higher amounts of crude fiber are best for most adult horses in light work.
Calcium and phosphorus, taken together, are probably the two most crucial mineral levels to note on a feed tag. They play a vital role in the health of the musculoskeletal system. All horses need calcium and phosphorus in their diets, but youngsters and broodmares in particular require higher levels of these nutrients.
A feed formulated for weanlings ought to have at least 0.7 percent calcium and 0.4 percent phosphorus, whereas an adult horse in average work requires only 0.3 percent calcium and 0.2 to 0.5 percent phosphorus. Most commercial feeds supply more than these minimum requirements. Levels as high as 0.9 percent calcium and 0.8 percent phosphorus are common, but they may range as low as 0.4 percent and 0.3 percent, respectively.
But just as important as the total quantities of each nutrient is the ratio of the two minerals to each other. A horse needs to consume 1.1 to 2 parts calcium for every part phosphorus in his diet. That's because the body needs an equal part of calcium in order to absorb phosphorus, and if that calcium is not present in the diet, it will be taken from other places--such as the bones--to accomplish the job. Although excessive calcium in the diet can lead to gastric ulcers and other conditions, it's generally better to err on the side of too much of this nutrient than too little--horses can tolerate as much as five to seven times the recommended calcium with no ill effects, so long as they also get adequate phosphorus.
Keep in mind that your horse will also be consuming minerals in his forage. Legume hay, such as alfalfa, is much higher in calcium than grass hays. Thus, if alfalfa is a staple of your horse's diet, he doesn't need as much calcium in his feed, and vice versa. Some feeds are formulated to complement different sources of forage; the label will specify whether it is meant to be fed with grass or alfalfa hays.
Copper, zinc and selenium:Copper and zinc play an important role in growth, bone and joint development, nerve function, and other vital processes. Selenium works in conjunction with vitamin E to support the immune and reproductive systems.
All of these trace minerals are also found in forages, but vary among crops, so small amounts are commonly added to commercial feeds. The recommended quantities for the average horse are 10 parts per million (ppm) copper, 40 ppm zinc and 0.1 ppm selenium. Feeds for broodmares have much higher amounts of copper and zinc to aid the development of the fetal skeleton.
Pay particular attention to the selenium content of a feed. Some commercial feeds provide much higher amounts of this mineral for those such as elite athletes or growing youngsters who may need more, and for horses living in parts of the United States with selenium-deficient soil. Keep in mind, however, that a relatively small overdose of selenium can be lethal. Do not give your horse high-selenium feed unless you are certain he needs it. Check with your veterinarian if you are unsure.
Salt is a crucial component of the equine diet and its elements--sodium and chloride--are electrolytes that play critical roles in many life functions, such as nerve function and maintaining internal fluid balances. Sodium and chloride are lost in high quantities when a horse sweats, and they are also the only electrolytes that are not naturally present in grains and grasses, so they must be replenished with supplemental salt. Fortunately, horses have a natural appetite for salt and will typically consume one to three ounces daily when it's offered as a free-choice supplement. Salt is also typically added in concentrate mixes at the rate of 0.5 percent for horses in light work and 1.0 percent for those who are more active.
Vitamin A, in international units (IU) per pound: Horses require a tremendous amount of vitamin A, which is needed to aid in vision, gene expression, immunity and many other functions. Vitamin A is abundant in alfalfa and green pasture, but levels of that nutrient drop rapidly after hay is cut--more than 50 percent is gone after about six months. Horses whose forage consists primarily of dried grass hay may benefit from feeds fortified with vitamin A. The average horse needs between 1,000 and 3,000 IU/lb. daily, but horses in rigorous work may require much more. The concentrations in commercial feeds typically range from 1,000 to 4,000 IU/lb.
Pay close attention to the feeding instructions when selecting a feed for your horse. Here you'll find a statement regarding the type of hay--grass or alfalfa--the feed is meant to accompany, as well as the suggested daily serving.
It's important to choose a feed whose suggested serving closely matches your horse's needs. All of the percentages and quantities listed under the guaranteed analysis pertain to that portion, and changing the serving size too much from the recommendation will also alter the other nutrient balances you are offering. In other words, if your horse needs fewer calories, and you scale his serving size in half, you are also offering him only half as much of the protein, calcium, Vitamin A and other crucial elements. It would be better to switch to a feed in which a single serving offers the right nutrient balances in a formula with less energy and more fiber. Another alternative would be to feed the lesser amount, but then provide a supplement that makes up the difference in lost nutrition.
Also, do not attempt to save money by diluting a balanced concentrate mix with a cheaper product. This practice will also alter the nutrient content of the total ration, and you may create deficiencies and detrimental interactions.
Equine nutrition may seem complicated, but feed companies invest a lot in research to develop formulations that meet the specific demands of a broad range of horses. All you need to do is read the feed labels and select the product best suited for your horse's age, level of work and special needs.
Kathy P. Anderson, PhD, is the horse extension specialist at the University of Nebraska-Lincoln. In addition to overseeing the horse extension program, she teaches undergraduate courses in equine management, reproduction and nutrition.
This article originally appeared in EQUUS 369, June 2008.