Minerals For Horses

By Eleanor Blazer
         "I’ll have 30 grams of calcium, 18 grams of phosphorus, a milligram of selenium, 400 milligrams of zinc…” 

          The feed store clerk is in shock.

          My horse, Babe, needs minerals and this is what the Sixth Revised Edition of Nutrient Requirements of Horses recommends for a 1,100 pound horse at light exercise.  I have a list of 16 minerals, but I can see by the clerk’s expression, this isn’t going to work.

          Minerals are essential nutrients – they must be provided by diet as the body cannot manufacture its own.

          Dietary minerals originate in the soil.  Plants take up available minerals; an animal – in this case a horse, eats the plants.  Mineral content of the plants vary due to location and plant variety.

          Sixteen minerals are considered essential to the horse’s diet.  They are divided into two categories: major minerals (macrominerals) and trace minerals (microminerals).  Major minerals are needed by the body in larger amounts than trace minerals.  Trace minerals are still very important to the health of the horse, but are needed in smaller amounts.

          There are seven major minerals: calcium (Ca), phosphorus (P), potassium (K), sodium (Na), chloride (Cl), magnesium (Mg) and sulfur (S).

          There are nine trace minerals: copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), iodine (I), selenium (Se), cobalt (Co), fluorine (F) and molybdenum (Mo).

          Minerals interact with each other.  For example: excessive amounts of calcium can interfere with iron absorption; calcium and phosphorus must be in the proper ratio for horses – one and a half (1 ˝) to two (2) parts calcium to one (1) part phosphorus. 

          Minerals also interact with vitamins.  Examples are: calcium requires vitamin D for absorption; selenium requires vitamin E.

          Salt (sodium chloride) is the only mineral for which horses have an appetite.  If they have access to free choice white salt they will usually consume enough to meet their requirements. 

          Offering a trace mineralized (TM) block is a waste of money.  If the horse does not feel a need for salt he will not utilize it, so will not consume any of the other minerals.  The salt will also limit consumption, lowering the intake of other minerals even if the horse does use the block.  

          Do not rely on a TM block to provide minerals.

          The best way to provide minerals, other than salt, is to start with the forage.  A hay analysis will tell you the minerals lacking in the forage.

If you can’t run a hay test, contact your local United States Department of Agriculture’s Cooperative Extension Service. They can tell you what minerals are lacking in your geographic area.  For example, many parts of the country are deficient in selenium.

          The next step is to find a balanced product that is designed for the age and activity level of your horse. 

          Read the feeding directions on the feed tag!

          If the product recommends a 1,100 pound horse at moderate activity level be fed five pounds a day, do not feed three pounds a day! Lowering the amount of feed may decrease calories, but the lower amount will not meet mineral needs.

          Find another product.  Your horse may be maintaining weight on forage, but still is deficient in minerals.  There are products that provide minerals without increasing calories; these are called ration balancers.

          Do not dilute a balanced product by adding oats.  If the feeding directions do not state grains can be added, don’t do it.  Find another product if your horse is too fat or too “hot” to handle.  When you lower the energy intake you are also lowering the mineral (and vitamin) intake.

          We can see fat on a horse.  We can see coat condition. But we can rarely see a mineral deficiency.  Luckily there are resources (feed products) available to insure our horses have a balanced diet.  


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