The goal of any equine nutrition program is to design a diet that will optimize the health of the horse. The first step in creating an equine ration is to use nature to show us what horses would consume without human intervention. This brings us to “The Natural Diet.”
Before the horse was domesticated, herds roamed grassland areas and consumed a natural diet. Historians postulate that wild horses consumed a diet of grass, browse and other vegetation, resulting in ingestion of a balanced diet. Fresh grass is rich in fat-soluble vitamins and omega-3 fatty acids, nutrients that are lost during the processing and storage of forage. It has been estimated that the natural diet of the grazing horse contained up to 5 times more omega-3 fatty acids than omega-6 fatty acids. Those higher concentrations of dietary omega-3 fatty acids result in the production of less potent inflammatory mediators compared to diets high in omega-6 fatty acids.
Modern feeding practices have removed horses from a complete grazing environment. Although some horses still have access to pasture grass, many more are fed either a combination of hay and grain or a grain-based supplemental commercial feed. This increase in grain-based feeds has resulted in an increase in the dietary concentration of omega-6 fatty acids and a decrease in the concentration of omega-3 fatty acids. In fact, it has been estimated that the modern horse diet provides up to 18 times more omega-6 than omega-3 acids.
The healthy horse at a physiologic state of maintenance can thrive without the calories, sugar, and starch present in the grain. Feeding too much grain can lead to problems such as colic, enteritis, colitis, OCD and laminitis. Furthermore, muscle diseases, including equine polysaccharide storage myopathy and recurrent exertional rhabdomyolysis, are worsened when high grain diets are fed. Foals that receive too many calories from grain can suffer complications associated with the developmental orthopedic disease. In recent years, obesity and equine metabolic syndrome have become widespread in the equine population and are largely the result of horses being overfed.