How many times have you read advertisements for commercial grain mixes that claim they provide everything your horse needs, can balance virtually any hay, eliminate the need for other supplements, avoid over supplementation? Can they really do that? 

If you’re going to put blind faith in your favorite company’s assurances, turn the page. This article isn’t for you.

Put It To Use

Start with your hay and determine what minerals are low and what ratios (calcium:phosphorus, magnesium:zinc, zinc:copper) need supplementing. Vitamins are important, too, of course, but it’s the minerals that can get you into nutritional jeopardy faster. Feed grain, if your horse needs the added calories, otherwise choose a mineral supplement. Our favorites are TDI-10 and TDI-30 (www.tdihorsefeeds.com 800-457-7577) and Triple Crown 12 and Triple Crown 30 (www.triplecrownfeed.com 800-451-9916). The  10, 12 and 30 indicate protein levels in the pellets. Maintain a proper bodyweight for your horse.

If you want to take a hard look at what feeds can and can’t do for your horse—and possibly understand why you’re not getting the optimal results you hoped for from your feeding program—read on.

We’ve been conditioned by advertising to think of a horse’s diet in terms of his grain mix. If asked what they feed, most people automatically say Brand X, Y% protein. This is fine, but it ignores a large part of the horse’s diet, his hay and/or pasture. Hay and pasture are much more than just fiber, fillers or something to chew on. A significant proportion of your horse’s nutrition, if not most of it, comes from this source.

In past issues, we’ve looked at many of the most readily available vitamin and mineral supplements to see how they fared against hay analyses from across the country. There were a few supplements and grain mixes that stood out as outperforming the others, but not one could correct all the deficiencies and imbalances in every hay. Fact is, there’s simply so much variation between hays that it’s impossible for any single supplement or commercial grain to do it all.

What's in There?
There’s no way to tell if your feeding program is adequate in protein/calories and balanced in minerals unless you actually know what those levels are. For the hay and pasture, you have to actually analyze or, second best, contact your local agricultural extension agent or state university to see if regional analysis figures are available. For the grain, unless you analyze it, you have to rely on the label information and there are many pitfalls here.

Some feeds, even those claiming to be “premium,” list only the minimum information, which means fiber, fat, crude protein, calcium and phosphorus. The ingredients list may be much longer, including the various base ingredients as well as added vitamins and minerals, but without knowing how much is in there you are totally in the dark as to whether or not it is appropriate for your situation.

The Intelligent Use Of Grains

The hype about supplemental grain mixes being essential to providing the horse the nutrition he needs has led to far too many horses being fed grain than actually need it. This in turn has created a significant problem with obesity with associated foot problems, joint overload and developmental problems in young horses. There’s also a problem with how people view their horse’s “body image.” Overweight horses have become so commonplace, many think that’s how they’re supposed to look. While the “hot” breeds, as well as hard-keeper individuals in other breeds, may need some grain to hold their weight even when not in work, for most horses, high-calorie grain mixes should be fed in extremely limited amounts, if at all. Below are some general guidelines, starting points to help you keep your horse properly nourished but without risking excess body weight. Maintenance: 1.5 to 2.0% of body weight (16.5 to 22 lbs. for an 1,100-lb. horse) of an 8.7+% protein hay for the lower rate of feeding, or a 6.5% protein hay for the higher rate, plus a mineral supplement to match the hay with 5 to 7 grams/day of additional lysine Light  Work: Free-choice hay or miniumum of 2 to 2.5% of body weight, depending on how easily the horse holds his condition. Minimum hay protein 8.2%. Mineral supplement to match. If hay protein is less than 8.2%, feed a combination protein and mineral supplement, 28 to 30% protein with 2 to 3% lysine. Moderate-To-Heavy Work: When horses are working too hard to hold their weight with even free-choice, properly supplemented hay, begin adding a high-quality commercial mix, beginning at 1 to 2 lbs. twice a day, increase as needed to hold a good weight. Is Your Horse A Good Weight? Except for pregnant mares, who should be carrying a little extra body fat going into the last stages of pregnancy, the healthiest weight for your horse is a body condition score of 5 to 5.5 on the Heineke scale.  The criteria for this body condition are: Topline/back flat, with no obvious spinal prominence, but no deep crease. Ribs not visible, but easily felt. Fat around tail base feels just slightly spongy. Withers nicely rounded, not bony. Neck blends smoothly into body.

When a nutrient is listed on the label under guaranteed analysis, the manufacturer must make sure the feed actually measures up to that number because state feed officials will be checking.

The longer the list of guaranteed nutrients, the higher the manufacturer’s commitment to quality likely is, and the better you will be able to tell if the feed is going to fulfill all your needs. Unfortunately, there are still a few problems. One is that labels only list minimum amounts in the feed (both minimum and maximum for calcium), not the actual amounts. 

With minerals, these minimum amounts represent primarily the amount of added mineral plus an average analysis fudge factor for lowest likely level in the base grains and other ingredients. Actual analysis figures have been as much as 100% higher (double the label amount), and mineral ratios may also be considerably different when actual analysis figures deviate significantly from the minimum guarantees.

We looked at the guaranteed-analysis figures for eight premium performance feeds from across the country, some nationwide brands, some regional. The minimum calcium varied from 0.3% to 0.85%, maximums from 0.6% to 1.25%; phosphorus 0.5 to 0.7%; copper 30 to 55 ppm; zinc 100 to 220 ppm; selenium 0.4 to 0.7 ppm and one feed didn’t specify selenium.

The information on iron content was only available for one feed, and only two of the eight specified magnesium and manganese. Therefore, the first stumbling block when trying to determine if a feed matches your hay/pasture is that you won’t have information on all the important minerals, and the information you do have is in minimums, not actual amounts.

Actual amounts can vary from year to year even if sources of ingredients are kept the same, as well as from formula to formula for feeds that vary the relative proportions of grains and other feed ingredients in their product.

How Much?
Obviously how much of any given nutrient—protein, vitamin, mineral, etc.—your horse gets from his feed will depend on how much of it you feed.  A horse on lay-up or turn-out getting only a pound or two of grain a day is vastly different from one in heavy work getting five to 10 pounds or more. This should be common sense, but a surprisingly number of people think they have their nutritional bases covered when they feed a commercial feed regardless of the amount the horse eats.

With some notable exceptions for feeds that are formulated to be a better match for regional hays, especially in areas where alfalfa feeding is common, most commercial feeds adhere more or less to a “One-A-Day” philosophy, where they contain (at least on minimum guarantee figures) a mineral profile that is fairly well-balanced for a horse. So far so good but, again, how much good this does the horse depends on how much of it he is eating and how well-balanced the hay/pasture are.

Mineral Deficiencies

A few commonly encountered problems that may have their roots in mineral deficiencies, or imbalances that can create deficiencies even when minerals are present in their minimum recommended amounts, include: Nervousness, sensitivity/    irritability or muscular problems (magnesium). Coat “bleaching,” red discoloration to dark manes and tails (copper). Fading of all coat colors (zinc). Poor hoof quality, skin problems (zinc). OCD (calcium, copper, zinc). Poor immunity and immune system derangements, e.g. allergy (all trace minerals).

Whether you choose to feed a sweet feed, pelledted feed or just plain oats, you're going to need to address mineral imbalances, based on your hay.

We looked at the calcium, phosphorus, copper, zinc and selenium figures for three nationwide hay samples and saw what happens combining 22 lbs. of these hays with 2, 5 and 10 pounds of a feed with a mineral profile that represents some middle-of-the-road minimum figures common in commercial premium horse feeds.  Note: Calcium:phosphorus ratios of as high as 6:1 are reported to be tolerated as long as phosphorus intake is adequate, at least short term. However, long-term effects of this and other mineral excesses on absorption of other minerals has not been studied.

When fed at 2 lbs./day, the horse still falls short for individual minimum requirements for at least one mineral with all these hay types. At 5 lbs./day, individual minimums are met for the minerals we have information on, at least for maintenance, so the “One-A-Day” concept is met. However, we still don’t know the status of magnesium, iron, manganese, iodine and cobalt, and we can’t be sure these numbers are accurate because the feed analyses are in terms of minimums, not actual content.

Remember, too, that the mineral ratios are important. As the amount of grain fed is increased, there is a more significant effect on mineral ratios in the total diet. Although they’re never completely corrected to ideal, at the high levels of feeding (10 lbs./day), the Ca:P (calcium to phosphorus ratio) and Cu:Z (copper to zinc ratio) are considerably improved. Once again, though, we’re only talking about the minerals listed on the bag. Most hays have generous, if not excessive, amounts of iron and manganese, borderline-to-low magnesium, and you have no way of knowing if the levels of those minerals in the feed are improving the situation, having no impact, or even making it worse.

Smart Feeding

Grazing a pasture with a variety of plants/grasses or feeding a variety of hay types usually helps to minimize mineral imbalances in this important part of the diet. When feeding 5 lbs. or more per day of a highly mineral-supplemented grain, don’t also feed a “multi” mineral/vitamin supplement. The most commonly encountered deficiencies are magnesium, copper, zinc, iodine and sometimes phosphorus. Hay analysis or regional analysis figures for the area where your hay was grown provide the best information regarding deficiencies and excesses. Consult your state university’s agriculture department for information. If you’re not satisfied with the results of your feeding program, consult an independent nutrition specialist rather than reaching for more supplements. Not only will the results be better, but the money you save by targeting specific needs will more than pay for the cost. “One-A-Day” Equine Formulas Taking a supplement that supplies all or part of daily mineral/vitamin requirements is much more likely to be beneficial for a human than a horse. The reason for this is simple: variety. We would never eat precisely the same meal, three times a day, 365 days a year. However, the number of horses with access to a variety of different plants and grasses to eat is rapidly shrinking. Many horses eat precisely the same grain and hay for months, even years, on end. This is especially important with minerals. The horse can guard against over-absorption of minerals to a limited extent by shutting down absorption pathways in the body that actively seek and bind minerals, pulling them into the intestinal cells. However, minerals are also absorbed in the spaces between cells and this process is not regulated. Consider free minerals inside the intestine as balls in a lottery machine. If you have 10 black balls (mineral X) for every 1 white ball (mineral Y), it’s easy to predict which color has the best chance of hitting the chute. This is one reason why mineral ratios are important. High concentrations of minerals that can bind to other minerals and prevent them from being absorbed will also take a greater toll on minerals that are in short supply to begin with. Putting a one-a-day into an imbalanced “soup” in the intestines doesn’t correct the basic problem.

What's It Mean?
What’s the real-life significance of this? Obviously few horses have their diets meticulously balanced, but they’re doing just fine anyway—or are they? But consider this: If all those supplemented grains and one-formula-fits-all supplements, designed along the “One-A-Day” lines, were really getting the job done, there wouldn’t be such a huge market for hoof supplements or skin/coat supplements.

Throwing an excess of minerals at the horse is not without its problems either. Enteroliths, urinary tract stones/gravel and performance-related problems such as thumps and tying-up may all have their roots in mineral excesses.

When fed at 10 lbs./day with 22 lbs. of hay, our “average” premium-supplemented grain was able to improve even the skewed mineral ratios for Ca:P and Cu:Z in alfalfa hay, but the diet ended up providing 825% of maintenance and 550% of moderate work requirements for calcium.

Horses with access to pastures containing a mix of grasses, or mixed grass hays, and up to 20% legumes (clover, alfalfa) are much more likely to do well with supplemented grains or set formula mineral supplements because their base diet has a better chance of being inherently fairly well-balanced.  Some people are even fortunate enough to have access to a single type of hay that happens to have a favorable mineral profile.

However, if you find yourself faced with one or more problems that likely have a component of mineral deficiency or imbalance,  it makes more sense to us to find out exactly what the problems in your horse’s base diet are (using hay analysis or regional analysis figures for your area) and supplementing only what’s needed in the correct amounts.

Bottom Line
Supplemented grains can help get the required minerals into your horse, but to have a significant effect on imbalances they have to be fed in high amounts, which can lead to excessive intakes of some minerals and may not always get the job done properly.

If you are relying on a supplemented grain, request a complete analysis, including all minerals, from the manufacturer and compare this to your hay’s (or region’s) requirements. If the feed manufacturer will not release this information to you, find one that will.