Healthy Muscle, Happy Horse

("Equine Muscle Structure" courtesy of BH Visual Art, target="blank" >www.bhvisualart.com

Recently I have been inundated with requests to consult on cases involving equine muscles: tying up, strains, EPSM (Equine Polysaccharide Storage Myopathy), and other primary muscle conditions. This is likely due to a number of reasons: the show season is coming to an end, miles are adding up and aches and injury are following; snow is finally clearing out of the high mountain regions and allowing horses to be taken on longer and steeper rides; and the summer heat is leading to overexertion and dehydration. Of course, muscles are important for every horse, whether for competition or just getting up that next hill in the North Cascades, and keeping those muscles as healthy as possible should be every horse owner’s goal. Like many things, prevention is a much better option than treating an emergency, so rather than discuss an individual muscle disease it makes more sense to look at what can be done to optimize muscle health.


Diet

Muscles get their energy by synthesizing ATP from ADP (don’t you wish you had stayed awake in biochemistry now?). One way to do this is called glycolysis, which uses the glygogen stored in muscle. The byproduct of this pathway is lactic acid, responsible for the “burn” we feel while working out. Another process oxidizes fat and results in the byproducts of carbon dioxide and water. Endurance horses become very efficient at using this cycle. The bottom line is that if horses have too much energy stored in the form of glycogen, and are exercised, it can result in a cascade of events that result in severe cramps, impaired blood supply to the muscles, permanent tissue damage and in some cases, severe kidney problems. Some animals are genetically predisposed to these events and have to be fed very carefully, to avoid them. Feeding concentrates (grain) in large amounts, or choosing feeds with high sugar concentrations can worsen the condition in predisposed horses, or set up less than ideal muscle function in horse that aren’t. Diets higher in fat and lower in carbohydrate can help minimize and possibly eliminate the problem in some cases, but this method of feeding is probably optimal for muscle function in all horses. This means feeding carbohydrate at less than 15% of the total weight of a diet and fat at more than 10% (in tough cases even lower carb and higher fat percentages are recommended). There are commercial feeds like Re-Leve, SafeChoice or Strategy that provide these proportions in a complete feed, but these goals can also be achieved by adding high levels of rice bran or corn oil to other diets. In any case, it’s a good place to start.

Supplements

Even with a good diet, and in animals that don’t have a specific muscle dysfunction, there are supplements that can improve muscle health and help with performance.

Selenium is a trace element important for muscle and thyroid function, two tissues vital for performance. Though not a common deficiency because selenium is often added to salt blocks and commercial feeds, horses with recurring muscle problems should have selenium levels checked. This is especially important information to know before arbitrarily starting a selenium supplement, because high levels can be toxic.

Vitamin E is an excellent antioxidant that can scavenge free-radicals and decrease muscle damage from exercise--microscopic tears that result in delayed onset muscle soreness (DOMS). Supplementation reduces the sore-muscle grumpiness of horses and helps that Monday morning ache of weekend-warrior trail horses. Most horses can get by on 1000-2000 IU per day, though horses with specific diseases and those in intense exercise can be given double this amount with no problem.

CoQ10 makes Vitamin E more available and improves its efficiency, so CoQ10 at 100mg per day in conjunction with Vitamin E should be considered for any horse in training.

Herbs

The Chinese have a unique view of muscles and performance. Exercise depletes the essential energies of the body (qi and blood) and if not replaced can lead to atrophy, cramps, and weakness that may lead to injury. There are many herbs that replace these energies. Take for example the formula Ba Zhen Tang, which uses eight herbs to replenish both qi and blood. In it, ginseng, atractylodes, poria mushroom and honey-fried licorice replenish qi while rhemannia, angelica, white peony root, and lovage root tonify blood. Often ginger and Chinese date are also added to help digestion. From a western perspective, this combination of herbs increases red blood cells, relieves muscle spasm, stimulates the immune system, and counters the effects of adrenal stress.

For athletes, additional herbs can be added to modify this classic formula. Two of the most famous are cordyceps (see image), which helps stamina and endurance by increasing oxygen utilization and eleuthero root, which is an adaptogen that helps the body deal with stress and fatigue.

Mares and nervous horses are more prone to cramps, likely due to hormonal changes in mares and tension in nervous horses. If cramping is situational, (a mare in heat, a spooky horse in a new environment) herbs can be given for this as well. Raspberry leaf can effectively mitigate some of the hormonal changes of estrus, and valerian root can help with anxiety. Of course, traditional Chinese formulas made up of multiple herbs to address specific imbalances of an individual are also available to treat such cases.

Horses with chronic muscle disease or damage from an injury are going to need a more aggressive approach, which often means combining a strict diet with supplements, massage, herbal formulas, and acupuncture.

Every horse, pasture ornament or FEI star, has muscles, and with sound nutritional and supplement choices, those muscles can be kept as happy and healthy as possible.