Nutrition is a specialty like any other scientific field. Despite this, it's common for people with no qualifications to offer nutrition advice. Many things you hear or read over and over again can be wrong.  Take this mini quiz to test your own equine nutrition knowledge.  The Answers are posted below.

When building a diet and deciding how much to feed, the first thing to be calculated is always:

  1. calorie needs

  2. protein needs

  3. fat requirements

  4. starch and sugar levels

  5. minerals

The mineral most likely to be present in any diet at levels far exceeding requirements is:

  1. calcium

  2. phosphorus

  3. chloride

  4. iron

  5. copper

The most common nutritional factor contributing to poor hoof quality is:

  1. low protein

  2. fatty acid deficiency

  3. trace mineral deficiency

  4. too much sugar

  5. silicon deficiency

Bioavailable sources of sulfur in the diet are:

  1. MSM

  2. sulfur containing amino acids

  3. flowers of sulfur (inorganic sulfur)

  4. sulfates

  5. Both 2. and 4.

What can cause inflammation in the horse's body:

  1. High omega-6 fatty acids

  2. High sugar/starch intake

  3. High copper intake

  4. Both 1. and 2.

  5. None of the above

True or False.   If you feed the recommended daily amount of a balancer or fortified feed, vitamin and mineral  deficiencies or imbalances are impossible.

Deficiency of which electrolyte causes alkalosis in endurance horses:

  1. sodium

  2. potassium

  3. chloride

  4. bicarbonate

  5. calcium

Compared to hay, fresh pasture always has higher levels of:

  1. vitamin E

  2. vitamin C

  3. fructan

  4. water

  5. all of the above

The most common trace mineral deficiencies in hay are:

  1. iodine

  2. selenium

  3. copper

  4. zinc

  5. all of the above

Horses differ from humans and small animals in the way they absorb:

  1. calcium

  2. protein

  3. fats

  4. iodine

  5. chromium

Assuming an equivalent adult body weight, which of these horses has the highest protein requirements:

  1. mare in late pregnancy

  2. a 2-year-old in race training

  3. yearling

  4. mare in early lactation

  5. horse recovering from surgery


1. The first thing calculated in designing a diet is the calorie requirement. Once you know that, you determine how much of each element of the diet to feed. After you know how much you will be feeding you can calculate how much protein, fat, minerals and vitamins that is providing.

2. Iron is by far the mineral present in greatest excess in most diets. I've never seen a diet where iron needed to be supplemented.

3. There are many nutritional issues that may show up as poor hoof quality but the most common is trace mineral imbalances and/or deficiencies. The healthier, tighter growth at the top of this horse's hoof occurred after mineral balancing with no other changes.

4. Sulfur-containing amino acids are the most important source of sulfur in the diet. The horse can also absorb and utilize sulfates. Contrary to popular opinion, sulfur from MSM does not become incorporated into body tissues. It is absorbed easily but the sulfur it contains is all excreted.

5. None of those listed factors will cause inflammation. Inflammation only occurs in reaction to something like an injury or illness. The diet may cause an imbalance in the homeostatic mechanisms the horse's body uses to balance inflammation but it can not actually cause inflammation.

6. The answer is False. Balancers may or may not provide enough supplementation to make sure individual requirements for nutrients are met, thus avoiding primary deficiencies, but secondary deficiencies often remain. A secondary deficiency is when the ratios between minerals are off, allowing minerals present in high amounts to essentially crowd out those in low amounts.

7.  Chloride is the electrolyte deficiency which causes alkalosis. Alkalosis is an excess of bicarbonate ions. To maintain electrical neutrality, the body strives to balance this equation: sodium + potassium = chloride +  bicarbonate. As chloride drops, bicarbonate must go up. This causes more binding of ionized calcium which interferes with muscle and gut function or can cause "thumps".

8. The answer is all of the above. Fresh grass has more water, vitamin E and vitamin C than hay. If it is a fructan producing species, it also has more fructan when live pasture as the grass continues to metabolize fructan stores after being cut.

9. Again, the answer is all of the above. Deficiencies of iodine, selenium, copper and zinc are very common.

10. Horses differ in the way they absorb calcium. In other animals, calcium absorption is hormonally regulated but the horse freely absorbs calcium and excretes any excess in the urine.

11. Lactating mares have a higher dietary protein requirement than any other age, class or use. Failure to provide it compromises her muscle mass but she can also break down key tissues like tendons and ligaments to free up the protein she needs to make milk.