There are ways to approach treatments logically to ensure their effectivenessYesterday, today, and tomorrow, there were, are, and will continue to be a plethora of elixirs, restoratives, maximizers, enhancers, preventatives, remedies, antidotes, cure-alls, and therapies. They are often touted as the treatment needed to hasten tissue rehabilitation and return an equine athlete back to performance, maintain peak performance, or to prevent loss of performance in the first place.
They take the form of feed additives, rub-ons, pour-ons, injectables, or therapeutic methods and devices. There are therapeutics targeted and designed for every tissue and body system in the horse. Some work, some do not, some help, some will not, but they all cost money or take precious time from trainers, grooms, veterinarians, or owners.
In time, some of these treatments, although scorned at first, turn out to be the therapeutic method of choice. However, many turn out to be useless and become part of the passing equine lore. Two positive recent examples of the successful phenomena are the use of DMSO and arthroscopy.
In the early years of DMSO usage, those associated with its use were often considered "quacks." It was not until years later that scientific research was advanced enough to show that DMSO was a potent oxygen free-radical scavenger that could minimize and prevent tissue damage. Likewise, when arthroscopy (use of a fiberoptic endoscope inside a joint) was first used in equine joint surgery, many considered it a poor second choice or non-choice to the older method of arthrotomy (use of an incision to expose an involved joint) to visualize and work within a joint. There was a learning curve that occurred before arthroscopy was routinely used and widely accepted.

Short-term fix or long-term solution
When dealing with any injury or illness, therapy may take the form of a short-term fix, a long-term solution, or a bridge between the two. A clear understanding between the horse owner, trainer, and veterinarian must exist in order for all therapeutic options to be considered.
A solid understanding of the basic form and function (anatomy and physiology) of the horse is important, not only to this discussion, but also to determine: 1) if a claim about a product has any merit; and 2) if the product's use is applicable to the current needs.
Many product claims, theories, and supportive documents are founded upon basic information of a horse's anatomy and physiology. Therefore, the better one's knowledge and understanding, the more rational and intelligent a decision becomes.
Part 1 of this three-part series will focus on the basics of nutrients, muscle, and energy production. Parts 2 and 3 will focus on a horse's reaction to injury and alternative internally-taken products to help horses, and on present and alternative therapy modalities, respectively.

Basics: Nutrition
Adult horses have the drive to ingest approximately 1.5%-to-2% of their body weight in feed per day. In the inactive 1,000-pound horse, this would be about 20 pounds of feed per day. Consequently, after eating this much, the horse would feel comfortably full. At least one pound of roughage per 100 pounds of body weight per day is important in providing normal gut fill, scratch, stretch, and function in a horse's intestinal tract. The amount (by weight) and type of hay, grain, or pasture will determine the nutritional level and benefits of the ration to a horse. This, taken in conjunction with a horse's nutritional needs based upon age, level of usage, and personality, will determine the fine tuning of a horse's ration.
There are six nutrient classifications. All of them are critically important to the horse. These nutrient categories are water, carbohydrates, proteins, fats, vitamins, and minerals. The calorie-providing (energy-producing) foodstuffs are the carbohydrates, proteins, and fats. From these six nutrient groups, which are consumed on a daily basis, come all of the tissues and reactions of a horse's body.

Water
Water is a plentiful and relatively inexpensive nutrient. It makes up 65%-to-85% of a foal's body weight. By the time a horse has become an adult, water makes up 45%-to-65% of its total body weight. Water is found within cells (intracellular) and outside cells (extracellular). The extracellular water is found in blood plasma, lymphocytes, interstitial fluids (between cells in a tissue), joint fluid, etc. Water is also critical to and found in large quantities in the digestive and urinary systems. Water is important to all body functions, including chemical reactions, cellular reactions, transportation of substances within the body, temperature regulation, lubrication, and shock-absorption in joints and body cavities. An average resting adult horse needs 10-to-15 gallons of water per day. This comes in the form of drinking, moisture content of the feed, and metabolic water that is generated within the body. Water loss for a horse occurs in sweat, urine, manure, breathing, and through the skin. One of the results of a reduction in water intake is a reduction in food intake.

Carbohydrates
Carbohydrates are made of sugars and starches. They occur as sugar, starch, and cellulose in feedstuffs. Carbohydrates provide energy (glucose and glycogen), are building blocks for other nutrients, and are stored as fat in a horse's body. The energy currency of muscle cells is provided by adenosine triphosphate (ATP) molecules. These molecules are produced within the muscle cells in mitochondria from the breakdown of glucose. There are several steps to this process. The storage form of glucose is glycogen. When energy is needed, the glycogen is broken down to glucose and it is then utilized to produce ATP. Consequently, muscle mitochondria is critical to muscle energy production and muscle contraction.

Fats
Biologically important fats (lipids) are the triglycerides (three fatty acids together = neutral fat), phospholipids (phosphorus + fatty acids), and sterols. The phospholipids are structural components of cell membranes, sterols are components of steroid hormones, and neutral fat is stored in the fat deposits. Fats also exist that contain carbohydrates and are called glycolipids. Fatty acids can be used as an energy source in the horse. They provide approximately 21Ú2 times more energy than carbohydrates. However, the rate of fatty acid availability from the blood to muscle cells is limited.

Proteins
Proteins are the connective and structural building blocks of the tissues, cells, cell chemical messengers, and soft tissue structures (skin, hair, and organs) of a horse's body. They provide structure, form, and function to the entire horse. Muscle cells contain contractile proteins, and there are collagen proteins that hold a horse's bones and connective tissues together.
Dietary proteins are essential nutrients because they are made up of large numbers of amino acids. These amino acids are used to build new proteins in the horse. There are 22 amino acids commonly found in horse proteins. Of these, ten are essential amino acids and need to be supplied in the diet because the horse cannot produce them fast enough to meet its need.
In addition, some proteins contain carbohydrates and are called glycoproteins or mucoproteins. Lipid-containing proteins are called lipoproteins.

Vitamins
Vitamins are potent, noncaloric, organic compounds needed in very small amounts. They cannot be made by the horse and, therefore, must be present in a horse's diet. The vitamins perform specific functions to promote growth, reproduction, and maintain health. Many of the vitamins function as coenzymes (cofactors) and regulate metabolism and permit specific cellular chemical reactions to occur. The vitamins are divided into two groups. The fat-soluble (provitamins) vitamins are A, D, E, and K. They are generally involved with regulation of the metabolism of structural units. The fat-soluble vitamins are excreted solely in the manure. The water-soluble vitamins are the B-complex vitamins and vitamin C. The B-complex vitamins are generally involved with energy and energy transfer. The water-soluble vitamins, although present in manure, are primarily excreted in the urine.

Minerals
Minerals are inorganic chemical elements. They are critical for the horse to build specific tissues and chemicals. These inorganic elements are considered essential mineral nutrients. The minerals are divided into two major groups. The major minerals are called macrominerals and are usually present in greater levels in a horse's body or required in proportionately larger amounts in the diet. This group includes calcium, phosphorus, sodium, chloride, magnesium, potassium, and sulfur. The trace minerals are called microminerals and are usually present in lower levels or required in very small amounts in the diet. The trace minerals include iron, copper, zinc, manganese, cobalt, iodine, selenium, molybdenum, and fluorine. The minerals are involved in all of a horse's cellular and systemic functions.

Muscles, energy, and training
Muscles contract due to the energy that is released from the breakdown of ATP. Oxygen is used to
burn "body fuels" for the generation of more ATP. These fuels can be carbohydrates, proteins, and/or fats, and are converted to acetyl coenzyme A, which is condensed to form citrate, which enters the Krebs cycle (citric acid cycle = TCA cycle) and is oxidized to form ATP. When ATP cannot be produced fast enough through this aerobic metabolic mechanism, energy can be supplied from creatine phosphate by anaerobic metabolism. This less efficient form of energy production results in the formation of lactic acid. Lactic acid cannot be removed from the muscle cells as rapidly as it is formed, and its accumulation is thought to be a contributing factor to muscle exhaustion in the horse.
Because muscle mitochondria is where ATP production occurs, it is critical to muscle energy production and muscle contraction. Training
increases both the number and size of the mitochondria. In addition, training also increases the capillary blood supply to muscle tissue, permitting a greater delivery of oxygen. This results in an increase of aerobic ATP production. Fatty acids provide approximately 21Ú2 times more energy than carbohydrates. However, the rate of fatty acid availability from
the blood to enter muscle cells and provide cell fuel is limited. Training can also increase the efficiency of the use of free fatty acids for cell fuel.
Summary
Many product claims, theories, and supportive documentation are founded upon basic information of the horse's anatomy and physiology.
Knowledge of basic principles provides a foundation for critical evaluation of the claims of the overabundant remedies, medications, and therapy methods that inundate the equine market. Sometimes "tincture of time" and "Mother Nature" are the best alternatives for our horses.