Mineral Deficiency In Horse Hay And Pasture

There is a common thought among horse owners that the mineral content of the soil and hay has been reduced to the point that horses are becoming mineral deficient. However, I do not see the data supporting this nor the horses developing a mineral deficiency. So I asked a successful farmer why this belief is so prevalent. His answer was honest and not surprising.

Plants require minerals in the soil to grow, but there is more to it. They also need the right microbes and pH (acid/base); if these are wrong, the plants will suffer. We are all aware of the gut microbiome in ourselves and our horses, but plants also need this bacterial relationship in the soil to live and thrive. Plants and bacteria have coexisted in a wild and natural environment for millions of years. However, the development of plant seeds that grow with a greater yield per acre and are being grown without any other species of plants removes more of the minerals with no increase of minerals being added back into the soil. In addition, this change alters the pH of the soil allowing the growth of acid-loving competition (moss, fungi) and altering the soil bacteria.

I have always assumed that if a farmer wants to remain profitable through the production of their crops, they would add the lost minerals to the soil before the next season. The farmer I talked with confirmed that this is what successful farmers do. They add mostly limestone (calcium carbonate), reducing the soil’s acidity while replacing the lost calcium. He also adds other organic matter, which feeds the soil bacteria and replenishes the minerals. Adding minerals requires testing the soil by the agricultural extension agent available in every state. Then the correct amount of minerals is added back into the field to assure the efficient development of the next seeding or growth.

In essence, the farmer told me that every successful farmer would prepare the soil for maximum harvest growth. Without this soil analysis and replenishment, the farmer will eventually fail due to sub-optimal crops.

Why Do Horse Owners Buy Bagged Minerals?

Why do horse owners say to me that the hay lacks minerals and that supplementing with minerals is necessary? There are two reasons that I can see. The first is that minerals can be bagged and sold for horses, and the horse owner feels they are necessary. The second reason is what the farmer told me. He said that farmers cut corners to increase profits. But then he added that the most common cause of mineral depletion in horse pastures is that horse owners are unaware that their fields also need supplementation. He suggests that horse owners should contact their ag extension agent, send in a soil sample, and then treat their pastures according to the results.

In other words, we are always concerned with our horses’ health but show little concern for the health of our pastures. Many horse owners have little pasture to care for, so minerals need to be found elsewhere. We rely on the farmer maintaining their hay cropland so that our hay has adequate minerals, but can we be sure? Some people test their hay for mineral content, among other factors. However, we all must remember that minerals can be found elsewhere (and not just in a bag). Water from the ground is filled with minerals. So are the mined salt licks most horse owners have in their stalls. I avoid the white salt licks (sodium chloride or NaCl with binders) and the red trace mineral licks (they have corn syrup and molasses). Both well water, mined salt, pasture, and hay, should have all the minerals a horse needs.

I wouldn’t say I like mineral supplements for three reasons. 1) where were the minerals produced and how were they stored, and for how long? 2) Where is the independently guaranteed analysis of what’s in the bag is equal to what the label says? If the mineral is a trace mineral, there is very little of it. The potential that it isn’t even in the bag is possible, and no one is testing them to assure that it is. 3) Why should we add a long list of minerals when most trace minerals are recycled by the horse, thus preventing their loss in the first place?

Finally, where are all the horses suffering from mineral deficiencies? I hear from every place I go throughout the US this, “You know, Doc, we are low in selenium in this area.” I mean, everywhere I go, I hear this, yet I do not see horses with any signs of a selenium deficiency.

But Is There Another Reason For A Mineral Deficiency?

All of you know that I think differently, so let me give you this thought. Getting a mineral from the food in the gut to come across the gut wall requires the mineral to be attached to one of a group of molecules called a ligand. The attachment is called chelation. The most common ligands are amino acids. Most minerals chelate to an amino acid which allows the mineral to come across the semi-permeable gut membrane and into our bodies. It is a regulatory process so that if we need a mineral, we chelate it. If we don’t need it,, we let it pass out of the body.

If you have been following me, you know that I believe most horses are protein deficient. The two reasons for this are: 1) horses fed inadequate amounts of high-quality protein with all the essential amino acids, and 2) the amino acids consumed by the horse for fuel rather than for the intended purpose of protein development caused by the excess feeding of glucose every day of the year. Could it be possible that due to the inadequate amounts of amino acids in the horse, a horse would be unable to absorb the needed minerals? When I read about the lack of copper, zinc, magnesium and other minerals, I never see whether the horse has addressed their need for daily high-quality protein. Rather, competition from other minerals such as iron is ruled the cause.

Are hay and soil low in minerals?

The answer is that maybe hay is low in minerals depending on the quality, and the only way to determine this is to test the hay. It is much more likely that the pasture, if not maintained with mineral applications through soil testing, is low in minerals,, causing your field to suffer and not your horse. On the other hand, if your horse is consuming groundwater and a mined salt lick, then they should have adequate mineral availability.

If you want to be sure your horses are getting enough minerals, then first be sure they are consuming adequate amounts of high-quality protein – and grass and legumes are NOT high-quality. Wild fields of pasture plants that change throughout the year fed to horses that do not receive sugar (starch) every day should have adequate amounts of protein. However, most horses kept today eat only one type of grass and one or two types of hay plus excessive amounts of starch, leading to protein loss. Adding high-quality protein to the daily feeding of horses causes the development of beautiful, lustrous hair coats, solid hooves, loss of the hay belly and an improved top line. It should also improve the absorption of any minerals the horse needs.

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