When shopping for mineral supplements, you’ll find no shortage of choices. You’ll also find no simple system for comparing the nutrients each supplement contains. As a matter of fact, if you compare the guaranteed-analysis labels, you’ll find that about the only thing they seem to have in common is the picture of a horse on the label. In addition, the mineral profiles of the different types of hays and grains we feed our horses are so varied that no single product can do it all — no matter what those advertisements tell you.
To help you choose the right mineral supplement for your horse, we compared 36 mineral-containing supplements. Because manufacturers use various systems for listing the guaranteed analysis, we converted all the nutrient figures so you could easily compare mineral levels product-to-product. In addition, we determined what hay types each supplement is most compatible with, listed important mineral ratios and, of course, commented on the overall strengths and weaknesses of each supplement.
Major And Trace
Major minerals, of course, are the ones horses need in large amounts, like calcium and phosphorus. Trace minerals, like selenium and zinc, are required in much smaller amounts. Regardless of the amount your horse requires, each is important to your horse’s health.
In addition, some minerals work in conjunction with each other, depending upon a proper ratio or balance in order to be properly used by the horse. For instance, your horse’s ideal calcium-phosphorus ratio should be 1.2:1 to 2:1. If you have too much phosphorus, such as when you feed oat hay, the higher phosphorus may interfere with your horse’s ability to properly absorb that calcium — even if the calcium is at a “perfect” amount. To counter this, you must feed more calcium.
The other important ratios you must consider are calcium to magnesium, which should be also be 2:1, and your ratio of zinc to manganese to copper, which should be 3:3:1. These ratios are often how well-meaning horse owners get themselves into nutritional trouble, feeding too much of one without balancing another.
Note: NRC recommendations, last published in 1989, focus on a total daily magnesium intake with no reference made to mineral ratios, but we believe, as do many others, that maintaining magnesium intake in the correct proportion to calcium is important. As with any mineral deficiency, individual animals will vary widely in how sensitive they are to magnesium deficiency. Common manifestations of inadequate magnesium intake are muscular stiffness or cramping, twitching in hard-working muscle groups, irritability, jumpiness, and sensitivity to touch and sound.
Bioavailability is how readily the body can digest and absorb a mineral source. Minerals may be in inorganic forms — as found in dirt — or organic forms, where they are bound to a protein or other biological molecule.
Although data specifically for horses is lacking, studies at the University of Guelph, using lambs, showed the bioavailability of chelated zinc was up to five times greater than inorganic zinc sources. Organic trace minerals are prevented from interacting with other minerals/vitamins in the mix or with bonding agents such as phytic acid (phytate) present in the diet, which could decrease their absorbability.
Chelated minerals are specially formulated to increase their absorption/availability, which means the minerals are more highly absorbed even though they may appear in lesser quantities. However, we’ve found most manufacturers still use the same amounts of the chelated forms, even though they probably don’t have to. Not all minerals are chelated, as sometimes the cost outweighs the benefit. In other words, it can be more economical to simply put in more of a certain mineral than for the manufacturer to use chelates.
Mineral intake is a combination of levels in the horse’s hay, pasture and grain. Although it’s easier to focus on the grain, especially fixed-formula fortified grains with a guaranteed analysis, the mineral concentrations in hay are higher and much more important. Hay is, and should be, the cornerstone of every horse’s diet. Knowing its mineral profile will allow you to pick an appropriate supplement.
You should start by stabilizing your hay source and having a hay analysis done to get precise mineral information. Even if you buy your hay in small amounts from a dealer, odds are your dealer uses a limited number of suppliers in the same geographical area and can work with you in guaranteeing as steady a supply as possible from the same source. The hay dealer may even have a hay analysis available. If not, you may contact the National Forage Testing Center at 402/333-7485 or your local extension agent.
If a hay analysis isn’t practical, you can use the National Research Council averages for the hay type you feed, which is what many manufacturers use when designing their supplement. Just remember your figures won’t be precise. Contact the National Research Council at 2101 Constitution Avenue, NW, Washington, DC 20418.
Grain Mineral Levels
Of course, you also have to balance the grain ration, especially if you’re using plain grains. Mineral supplements are primarily formulated to complement/correct mineral deficiencies in hays. They don’t necessarily take into account how the picture changes when you feed grain.
Unsupplemented grains have a reverse calcium:phosphorus, meaning much more phosphorus than calcium, while the most popular hays are basically the opposite. A grain’s calcium:magnesium is also reversed, between 1:2 and 1:3. This helps with high-calcium hays, but the percentage of magnesium that grain contains is much lower than most hays, so the contribution to total magnesium intake is not much. On the trace-mineral front, all three of the commonly used grains — oats, corn and barley — are low in copper, both in total amount and in proportion of copper compared to zinc and manganese.
With commercial grain mixes formulated for horses, the job is pretty easy. Federal regulations require that if a grain is labeled for horses, it must contain mineral levels appropriate for horses, at least on the major-mineral end (calcium, phosphorus). Most companies also balance copper, zinc and manganese.
If full mineral information isn’t on the bag, call the manufacturer and ask. Even an economy grain mix specifically for horses should have major minerals balanced. They may not be at high-enough levels, especially to compensate for hay deficiencies, but at least the ratios will be correct.
Mid-price to top-of-the-line performance horse feeds usually contain sufficient additional minerals to supplement a diet based on common hays. They basically work best with timothy, but even with other grass hays using these grains goes a long way toward meeting mineral needs without additional supplementation.
In general, using supplemented grains will bring levels of trace minerals, except selenium, into at least the minimal dietary requirement range. However, it may not correct imbalances betw een them. Deficiencies/imbalances are likely to still exist on the major-mineral front. Changing the relative proportions of hay and grain fed will, of course, change these numbers.
Note: We like Southern States/Agway Legends 12 as a well-supplemented, moderately priced grain mix. To tell if your grain measures up, check the label. If calcium is over .5% and copper over 40 ppm, it’s likely a well-supplemented grain.
Commercial Mineral Supplements
When we looked at our mineral products, we didn’t really find outright “bad” supplements. What we did find, however, are a number of supplements that won’t work well with certain diet types, making them “bad” for some horses. Our comments and appropriate-diet sections list the pluses and shortcomings we see for these supplements.
We arranged products alphabetically. The cost information per dose refers to the manufacturer’s recommended dose. This doesn’t necessarily correlate with how much you need to feed your horse. For example, a manufacturer can’t accurately list a correct dose for a calcium/phosphorus supplement when so many different hays may be used. An orchardgrass-based diet needs up to 30+ grams per day of calcium to achieve correct mineral balances. On the other hand, fescue and oat hay need about half that, and timothy and alfalfa are already adequate.
Comparing products can be difficult as one company may use grams, another milligrams and yet another ppm or parts per million. To help you compare products, we did the conversions. The mineral content is listed in our chart as a percentage for the major minerals and ppm for trace. If you want to convert this to grams-per-ounce for major minerals, multiply 28.4 by the percentage. For example, 10%: 28.4 x 0.10 = 2.84 grams/ounce. For trace minerals, multiply by 0.0284; e.g. 2000 ppm: 2000 x 0.0284 = 56.8 mg/ounce.
Watch The Iron
Horses are rarely, if ever, iron deficient. Hays already provide twice the iron a horse needs. The ratio of required iron to copper is about 4:1. Too much iron interferes with absorption of calcium, zinc, copper and manganese and can lead to problems ranging from inflammatory tendencies to actual organ damage.
In addition, iron is a common contaminant in some mineral sources, with levels as high as 26,700 ppm (requirement is 50) in bone meal and up to 19,000 ppm in inorganic calcium and phosphorus sources. Check the labels. If it’s not on there, but the supplement contains things like dicalcium phosphate, call the manufacturer and ask the iron level. You want to stay at or under that 4:1 ratio of iron to copper.
Check labels closely to see if all the information you need, and deserve, is there. “Analysis” means the numbers listed are what is typically found in a batch. Yours could be different. A “guaranteed analysis” means just that — you can count on the numbers.
Be sure all the minerals listed in the ingredients list also show up on the analysis. Some manufacturers prefer not to disclose amounts for fear someone will copy their formula or simply don’t want to do the quality control necessary to list ingredients on a guaranteed analysis. We would avoid any supplement that won’t give you the information you need to balance your horse’s diet.
You must choose your supplement based on your horse’s hay consumption. Our recommendations assume that you’re feeding either no grain or an already balanced, commercial fixed-formula fortified grain, like Legends sweet feed.
Also With This Article
Click here to view “Mineral Deficiency Symptoms.”
Click here to view “Comparison Of Supplements With Emphasis On Mineral Levels.”
Click here to view “Our Picks: Mineral Supplements.”