Like other animals, horses require vitamins for normal body functions. These requirements will be met by vitamins naturally present in feed, supplementary sources and in the case of B Group vitamins, may be supplied by microbial synthesis in the intestinal tract.

Vitamins can be separated into two major groups: the fat soluble vitamins (A, D, E and K) and the water soluble vitamins (vitamin C and the B group vitamins). Water soluble vitamins are relatively non toxic when supplied in excess of requirements, however, excess of the fat soluble vitamins A and D can cause serious problems.

Borderline deficiencies of vitamins may exist without the horse showing any observable symptoms. When this occurs, growth, reproduction and performance may be affected.

The table (on page 8) shows the functions of the various vitamins in the horse.

The Importance of Vitamins in the Diet of the Horse in Work

Horses in work have been shown to have increased requirements for certain vitamins over that which is required for maintenance. Vitamins A, D3, E and the B Group vitamins should be added to the ration. It is risky to rely on nature to supply the vitamin needs of the horse in work.

Vitamin A, naturally present in green forage can be adversely affected when that forage is made into hay. Excessive weathering, improper curing and extended storage can all deplete the hay of vitamin A. In addition, stabled horses usually have very little access to fresh green grass, therefore vitamin A must be added to the diet. *Folactin Blue will be of assistance for this problem.

Vitamin D is synthesised in the horse on exposure to sunlight. Most stabled horses get very little sunlight, thereby decreasing the amount of vitamin D3 they can synthesise, therefore supplementation is usually necessary.

Recent research has highlighted the importance of vitamin E. Addition of vitamin E to the diet (approximately 1000mg) can improve the immune system, often improve endurance and can actually improve performance. It is also believed that the addition of vitamin E to the diet may be beneficial in calming an erratic horse, although this is not as yet proven.

The B Group vitamins are primarily involved in energy metabolism, therefore, the horse in work has an increased requirement for these (Thiamine and Folic Acid in particular) which cannot be met by the intestinal synthesis or natural sources.

In fact, in most cases, intestinal synthesis can be greatly diminished by the high concentrate diet fed. Supplementing the ration with Folactin Blue (Vitamin A, D3, Folic Acid and Inositol) and Salkavite (Vitamins E, B Group vitamins including Folic Acid) at the recommended dose rates, will ensure that adequate levels of vitamins are included in the diet.

In circumstances such as convalescence; during periods of peak stress (travelling horses interstate, etc.) and whilst spelling, the inclusion of Aminovite Plus (multi-vitamin supplement) will ensure adequate dietary vitamins.

Water

Water is the cheapest nutrient and the one needed in the largest quantity, and yet it is often neglected. A horse, or any other animal, will survive longer without feed than without water. A 450/500kb horse can drink anything between 20 and 80 litres (4.5-18 gallons) of water (or even more), depending on the type of feed it is fed, the intensity and duration of work and the climate. During hot, humid weather, horses will often drink large amounts (and urinate more) in an effort to cool down their body temperature, because sweating is ineffective.

Water should be freely available at all times except immediately following exercise. Since dehydration is quite common in horses in work, it is imperative that water (and water containers) be kept very clean to encourage horses to drink. Frequent inspection of water supply and cleaning of automatic waterers and buckets is essential.