MINERALS: Necessary in Small Amounts  

MINERALS: Necessary in Small Amounts   Last month we looked at the role of the different vitamins, where they can be found, and what can happen if the horse has too little or too much. This month, we’ll do the same with minerals. Minerals are found in forages, feeds, and supplements. Remember that minerals are inorganic: those found in forages have been taken up by the plant and the amount varies depending on the growing conditions. To make things confusing, some are listed as “organic minerals” because they are bound to an organic substance such as proteins or amino acids. This shouldn’t be confused with the foods that are labeled “organic” in the grocery store- different concept entirely! It’s thought that the “organic” minerals are more bioavailable, or more easily used by the horse. Minerals are needed in small amounts. I’m not going to tell you how much your horse needs, as that is a conversation to have with your veterinarian. Every horse is an individual and should be fed as such. Your horse’s requirements will vary depending on his age, health, use, and other factors. Sometimes it’s not the total amount of minerals that matters, but its proportion to other minerals. We talked about this previously when we touched on the concept of limiting factors in amino acids. You can think of one mineral or one amino acid as a key: using it unlocks the potential of other minerals. If you don’t have enough (or the key is too small for the lock), it won’t unlock and the other minerals can’t do their jobs. If you have too much (or the key is too big) the other minerals can be blocked. So…Goldilocks moment here…more isn’t better. Not enough isn’t good either. Minerals are generally categorized into two groups: major and trace. “Major” does not mean that the horse needs large amounts of these minerals. “Trace” means that the horse needs smaller amounts of these minerals than he does of the “major” minerals. Not very helpful, right? The minerals that are considered “major” are: calcium, phosphorous, sodium, chloride, magnesium, potassium and sulfur. We’ll quickly talk about what they do and where they are found in the horse’s diet. Calcium and phosphorous work together as a team. This is a case where the proportion is as important as the amount. The ratio of calcium to phosphorous should be 2:1 ideally, or two parts calcium to one part phosphorous. This can vary depending on your horse’s age. Youngsters have a different need than mature horses. Talk with your vet, review your feed, and analyze your hay because it all matters when you are trying to develop good bone in a young horse. Even if your ratio is correct, your young horse can develop bone issues if he isn’t getting enough calcium and phosphorous. In addition to being very important for bone development, calcium also aids in blood-clotting, heart rate metabolism, and muscle function. Luckily, the horse can tolerate a high amount of calcium as long as the phosphorous ratio is sufficient but check with your veterinarian if you have concerns. Phosphorous helps in the metabolism of carbs, fats, and vitamins, and helps with kidney function and the repair of cells. Important things! Calcium is found in grasses and legumes. Alfalfa tends to have a higher level than grasses. Phosphorous is also found in grasses but more so in grains such as oats and wheat bran. In fact, the calcium/phosphorous level in grains tends to be inverted, meaning that there is more phosphorous than calcium. Why does it matter? Because too much phosphorous is bad. It blocks the uptake of the available calcium and can lead to bone problems. Let me put this another way to help you remember. If you tell me that you feed oats and give bran mashes, I’m going to ask you, point-blank, what you are doing to correct the calcium/phosphorous ratio. And I’m going to stare at you until you give me an answer! Sodium and chloride are two more major minerals that we can address as one, because we know the combination more commonly as salt. We could spend a whole article on salt but for now we’ll just say that the horse needs about two ounces a day to help regulate his blood, conduct electrical impulses to his muscles, trigger his need to drink, and keep all his body systems performing. Commercial feeds usually have only a small amount, so ALWAYS offer free choice salt. It can be either loose or in a brick form, but it should always be accessible. The horse will seldom take too much but he can tolerate an excess generally if he has access to clean, fresh water. If he does have too much salt, it can lead to diarrhea, hind-end paralysis, and even death. If he doesn’t have enough, he will display dehydration, muscle weakness, incoordination, and decreased ability to sweat. Salt deficiency can happen very quickly as the horse sweats so his intake is something you should monitor consistently. It is critical and the horse must have it. Three more major minerals are magnesium, potassium, and sulfur. These are found in quality forages, but the plant’s ability to take up these minerals can vary depending on the weather, soil, and overall plant health. It isn’t feasible to test your horse’s pasture, but you can have your hay analyzed to determine the mineral content. Quality commercial feeds and ration balancers will also list the amount of these minerals. There is a lot of research being done on magnesium in the horse’s diet, with some interesting results. Magnesium is one of the major minerals in bone, and it has a role in over 300 enzyme reactions in the horse’s body. It’s important in nerve function and in muscles. It works antagonistically or against calcium in contracting and relaxing muscles. We’re starting to realize that the calcium:magnesium ratio is important and should be between 2.5: 1 and 3:1. Luckily, most forages and