Vitamins  are vital to maintaining good health, so a good understanding of what vitamins  actually do for the body is very important. Below you will find a listing of some of the major vitamins, their function and effect on the body. Included are recommended supplements for particular vitamins. Please Note: Your veterinarian should always be consulted regarding the diet and vitamin/mineral/nutrient intake of your horse.


VITAMIN A

Fat-soluble, antioxidant vitamin. Important for proper eye function, healthy skin and hooves. Needed to maintain healthy epithelial tissue in the respiratory, digestive and reproductive tracts. Regulates bone development in young growing horses.

DEFICIENCY: In horses, Vitamin A deficiency can cause night blindness, prolonged shedding, progressive weakness, sensitivity to light, excessive tearing, dry hair coat, anorexia, diarrhea, decreased growth, impaired mineral deposition, impaired intestinal absorption and susceptibility to infections of the respiratory and reproductive tracts.

TOXICITY: Too much Vitamin A in horses has been known to cause bone fragility, abnormal growth of bone tissue and sloughing off of epithelial tissue.

VITAMIN B COMPLEX

A group of water soluble vitamins which are necessary for the metabolism of nutrients (fats, carbohydrates and proteins). Excess levels of water soluble vitamins are usually excreted in urine.

THIAMIN (B1)

Thiamin is required for the metabolism of carbohydrates and helps with the proper function of the nervous system.

DEFICIENCY: Thiamin deficiency in horses can cause abnormal slowing of the heart rate (bradycardia), muscular incoordination (ataxia), localized muscular contractions which are visible under the skin, periodic hypothermia of the extremities, skipped heartbeats and loss of appetite and weight.

RIBOFLAVIN (B2)

Riboflavin is essential for energy metabolism and nervous system function. Contained in leafy, green hay and good pasture forage.

DEFICIENCY: Deficiency has not been found in horses. Symptoms of deficiency in other species include rough hair coat, atrophy (wasting away) of the outer skin and hair follicles, dermatitis (skin inflammation), conjunctivitis (inflammation of the tissue covering the eyeball) with discharge, abnormal light sensitivity and excessive tearing.

VITAMIN B-12

Vitamin B-12's most important functions are to assist in the production of red blood cells and in the utilization of proteins, fats and carbohydrates in feed. B-12 helps convert propionic acid, a primary volatile fatty acid produced via synthesis in the gut. Many horsemen believe that B-12 builds hemoglobin in red blood cells, which increases the oxygen transport capacity of the blood, thus making supplementation useful for racehorses.

DEFICIENCY: Vitamin B-12 is the only B vitamin which is not produced by plants. B-12 deficiencies have not been reported in horses, however, it is generally accepted that horses that are stressed, anemic, have severe parasitic conditions or are in generally poor health may benefit from supplementation. Horses who ingest poor quality forages may also benefit. Symptoms of deficiency in other species include anemia, poor appetite, weight loss, irritability, poor growth, impaired reproductive performance, rough hair coat, hindquarter incoordination and unsteady gait. Neurological problems have also been associated with B-12 deficiency.

NIACIN

Niacin is a term for 2 compounds with equal nutritional value: nicotinic acid and nicotinamide. Niacin is essential to respiration on a cellular level and also to metabolism. It is believed niacin is synthesized by bacteria in the hindgut. The amino acid tryptophan must be present for synthesis of niacin to occur.

PANTOTHENIC ACID (B3)

Pantothenic acid is a part of several important coenzymes, and plays a part in protein, fat and carbohydrate utilization. In most cases, the horse's body can synthesize adequate amounts.

FOLIC ACID

Folacin is a group of related substances of which folic acid is the most useful form in good nutrition. Folacin is necessary for the formation of red blood cells and cell metabolism. It also acts as a coenzyme for several enzymes involved in metabolism.

DEFICIENCY: Folic acid deficiency has not been identified in the equine, but a type of anemia due to folic acid deficiency has been found in other species. Active stabled horses, particularly racehorses can benefit from folic acid supplements.

BIOTIN

Biotin plays an important role as a coenzyme in the metabolism of proteins, carbohydrates and fats. Biotin supplementation has been show in studies to improve a poor quality hoof by strengthening the hoof wall.

DEFICIENCY: Extremely rare, never documented in the equine. Considerable amounts are synthesized by intestinal microflora, but if mold is present in the horse's feed it can inhibit the body's ability to utilize biotin.

VITAMIN B-6 (PYROXIDINE)

Pyroxidine is a vital part of the enzyme system and very important to the metabolism of proteins, fats and carbohydrates. It is also vital to the normal function of the nervous and immune systems. The essential amino acid tryptophan also depends on pyroxidine for its utilization. Adequate amounts of riboflavin and niacin are required in the diet for pyroxidine to be used nutritionally.

VITAMIN C

Water-soluble, antioxidant. Essential to the formation of collagen (an essential component of cartilage), lysine, an essential amino acid and proline, a non-essential amino acid. It is also believed to interact with iron and many B-complex vitamins. Vitamin C is synthesized in the liver and other body cells. Studies suggest supplementation reduces epistaxis (bleeding from the nose), increases sperm quality and improves breeding performance.

DEFICIENCY: Deficiency of Vitamin C has not been reported in horses, however, supplements may be useful during hot weather and periods of stress, growth and high performance.

VITAMIN D

Fat soluble vitamin. Promotes the proper absorption, transportation and metabolism of calcium and phosphorus. Vitamin D is critical to proper growth. It is fat soluble, so some amounts are stored in the liver and fatty tissues. The 2 major sources of Vitamin D are sunlight and sun cured hay. Supplements are usually required by stabled horses with limited or no time outdoors.

DEFICIENCY: In experimental conditions, Vitamin D deficiency caused reduced growth rate, bone weakness, failure of normal bone calcification, increased bone demineralization, lameness and loss of appetite. Vitamin D deprivation also caused large amounts of calcium to be excreted in the feces.

TOXICITY: Excess Vitamin D causes improper transport of calcium, thus causing calcium deposits in soft tissues. Results in loss of proper joint function, calcification (hardening) of soft tissues and abnormal enlargement of the skull and jaw. Consult your vet before feeding. Ingestion of Wild Jasmine, a noxious weed, produces similar symptoms to Vitamin D toxicity.

VITAMIN E

Fat soluble, antioxidant. Essential for growth, proper muscle development and function, oxygen transport and red blood cell stability. Believed important to the proper function equine immune system. Acts as a vasodilator: a compound which opens up blood vessels so that blood flows more freely through tissues. Also a cellular level antioxidant which prevents formation of toxic oxide compounds in the tissues during periods of intense exercise. Closely related to selenium.

DEFICIENCY: Vitamin E deficiency in horses causes swelling of the joints, muscle degeneration and ataxia (loss of coordination). Also linked to a form of wobblers syndrome, a disease which affects the spinal cord and column.

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