Like a gleaming coat, healthy hooves are a reflection of a horse’s overall state of health and nutritional status. Common factors affecting the quality of the hoof are genetics, environment, correct trimming, and nutrition. Optimal nutrition, based on the horse’s needs, is a key element in encouraging strong, healthy hooves. Let’s take a look at the components of a good feeding program.
Horses evolved as constant grazers of high fiber, low energy forage. Many health problems such as colic and laminitis can be avoided by keeping the horse on a simple, balanced low sugar grass hay diet. The equine digestive system is designed to break down fiber by means of microbial fermentation in the large intestine. Fiber is a significant source of energy for horses and many horses can get all of their protein and energy needs from quality hay alone. Because some grass hays may contain surprisingly high levels of sugar, horses that are easy keepers or insulin resistant should be fed low sugar hay. Sugar and starch content can be tested by sending a sample to a forage testing laboratory such as Equi-Analytical (equi-analytical.com).
Horses that work hard, such as endurance or racehorses, will perform best with a higher carbohydrate diet, including grains. Carbohydrates from grains (starches) are digested by enzymes in the small intestine and converted into glucose for readily available energy. Grains need to be slowly introduced to the horse’s diet and fed in several small meals rather than all at once. Excess starch that passes from the small intestine to the large intestine may result in carbohydrate overload, which can result in colic or laminitis. When the horse’s workload is reduced for any reason, the grain portion of the diet needs to be reduced accordingly. For many moderately worked horses, beet pulp, a high energy fiber, can substitute for most or all of the grain.
Protein is required for growth and tissue repair. Protein requirements increase slightly with exercise, but the protein to calorie ratio does not. There are 22 different amino acids that are the building blocks of protein. 10 of those amino acids are called “essential amino acids” and must be present in the horse’s diet – lysine, methionine, arginine, histidine, isoleucine, leucine, phenylalanine, threonine, tryptophan, and valine. Lysine is commonly low in mature grass hay rations and must be supplemented, particularly for growing horses. Mature horses at maintenance are less sensitive to protein quality than growing horses, but protein needs should never be overlooked. According to the National Research Council guidelines, a mature horse needs approximately 23 – 30 grams of lysine daily for maintenance. Most grass hays only contain .3 – .6% lysine, however, a few pounds of alfalfa can supply the lysine needs of adult horses. Lysine may also be supplemented by adding other feeds, such as beet pulp, flax, rice bran and sunflower seeds. Methionine is another amino acid that is important for healthy hoof growth and, like lysine, is usually deficient in grass hay diets. The actual requirements for methionine in the horse have not been established, but have been estimated to be roughly 25% of the levels for lysine.
A horse’s natural diet is low in fat. Most grass hays contain 1-3% fat. Horses do require certain essential fatty acids, however, and omega 3 and 6 are important for good health. Most horses get sufficient omega 6 in their regular diets, but unless they have access to green grass, omega 3 needs to be supplemented. Feeding 4 oz. daily of freshly ground flax seed will supply sufficient levels of omega 3 fatty acids. A 4 to 1 ratio of omega 3 and omega 6 seems to work well for most horses. Horses that are prone to allergies, such as sweet itch (caused by gnat bites) often respond well to the addition of 1⁄2 – 1 cup of ground flax seed to the daily diet.
Adding fat in the form of corn oil or other stabilized oils to a horse’s diet is a common practice for increasing calories without adding carbohydrates. These stabilized oils, however, do not supply omega 3 essential fatty acids. Processing oils to remain stable destroys fragile essential fatty acids, the same way that exposure to light, heat and oxygen does. Fat does provide concentrated calories, but it does not build muscle, bone or connective tissue. While horses are able to digest and utilize high fat diets, it is best to avoid them for the serious athlete. High fat diets have been linked to insulin resistance in ponies and should be avoided in insulin resistant horses.
Minerals are involved in the formation of bone, tissues, metabolism and energy use, and many bodily functions. A proper balance of minerals is also important in hoof growth and quality.
Calcium and phosphorus and their ratio to each other are related to normal hoof development. Calcium is needed for laminar attachment in the hoof horn. Excess phosphorus can block the absorption of calcium from the small intestine. This can result in a calcium deficiency and cause weak and abnormal bones.
Magnesium is important for a properly functioning nervous system, metabolism, and energy regulation. Magnesium deficient diets can induce insulin resistance, while magnesium rich diets along with exercise may help prevent it. Magnesium deficiency and insulin resistance are also very commonly found in horses that are obese, with abnormal fat deposits like large crests or fat deposits at odd places on their bodies. High calcium diets can interfere with absorption of magnesium. Ideally, aim for a 1.5 – 2:1:1 ratio of calcium to phosphorus and magnesium.
Trace minerals that are important in equine diets include iron, copper, zinc, manganese, cobalt, iodine and selenium. These minerals are referred to as “trace” because they are only needed in very small amounts, but they are still very important. Like calcium and phosphorus, trace minerals need to be in the correct ratios with each other, in addition to being present in the proper amounts. Too much of one mineral can interfere with absorption of another. For instance, high levels of iron can compete for absorption of copper and zinc. High levels of zinc can create a copper deficiency. The recommended amounts listed in the 2007 NRC “Nutrient Requirements of Horses” for a mature horse are a ratio of 4:4:4:1 for iron, zinc and manganese to copper. Supplemental copper and zinc are often added to equine diets to make up for deficiencies and compensate for high iron forage. Manganese levels can vary, depending on geographic location and soil conditions.
Some trace minerals such as selenium have a fairly narrow margin of safety. Selenium is an important antioxidant. It is needed for muscle function, thyroid hormone metabolism and a healthy immune system. Toxicity is characterized by loss of appetite, loss of mane and tail hair, and in the severe form, blindness, loss of the hoof wall, paralysis, and death.
Excesses of iodine will produce the same symptom (goiter) as too little. Iodine is essential for the synthesis of thyroid hormones that regulate metabolism. Kelp is a very rich source of iodine and a horse regularly fed kelp based supplements may run the risk of an excess of iodine.
When to supplement
How do you know if your horse needs supplementation? Start with the greatest part of your horse’s diet – hay. Most full sized adult horses consume 15 – 25 lbs of hay per day. If you can, you should obtain an analysis of your hay and determine what is in it. You can’t tell just by looking at it or going by what kind of hay it is. For instance, we know that alfalfa is usually high in protein and calcium compared to grass/cereal hays, but other nutrients can vary widely depending on soil and growing conditions. Since I started testing my local hay in 2004, I have accumulated some interesting data on common deficiencies and excesses in west coast hay. A good source for data about hay is the Equi-Analytical Laboratories website.
The most common finding in hay is high iron and very low copper and zinc. Excess iron is not beneficial for horses and can interfere with copper absorption, which is already in short supply. To make matters worse, feed companies often add more iron to their products. I have tested several brands of senior feeds and found that the iron levels were over twenty times higher than what they should have been according to NRC guidelines. Feed companies are not required to list iron levels on their tags, so a consumer has no way of knowing how much iron is in a product without the expense of sending a sample to the lab. Sometimes you can ask a feed company how much iron is in their products and they will tell you how much they add, but that is not the same as the actual amount present in the feed.
Before you decide to shop for a supplement, read the National Research Council book, “Nutrient Requirements of Horses”. Understand what your horse does or doesn’t need. Many expensive products are full of ingredients that your horse might not need or benefit from. You can look up the NRC recommendations for your horse, according to age, weight and activity level, by going to the calculator at http://nrc88.nas.edu/nrh/
Listed below are the recommendations for a mature 1,100 lb. horse at maintenance.
* Crude Protein 540 – 720 grams
* Lysine 23 – 31 grams
* Calcium 20 grams
* Phosphorus 14 grams
* Magnesium 7.5 grams
* Potassium 25 grams
* Sodium 10 grams
* Chloride 40 grams
* Sulfur 15 grams
* Copper 100 mg
* Zinc 400 mg
* Iron 400 mg
* Manganese 400 mg
* Iodine 3.5 mg
* Selenium 1 mg
The nutrient requirements for horses is based upon the National Research Council “Nutrient Requirements of Horses” sixth revised edition (2007).
Sally Hugg is a hoof care professional and developer of the equine supplement “California Trace”.
Hoof care background: AANHCP (2006 – 2007) and founding member of Pacific Hoof Care Practitioners (PHCP).
Studies: Dr. Kellon’s online courses “NRC Plus”, “Nutrition for the Performance Horse”, and “Nutrition as Therapy”.
With over 35 years of experience as a horse owner and rider, Sally takes a special interest in the health and well being of horses. She teaches a popular one day class about equine nutrition for horse owners and hoof care professionals called “Between the Twines”, based on the NRC publication “Nutrient Requirements of Horses”. Her hoof care practice in northern California focuses on the balanced diet as a cornerstone to creating healthy hooves.