What is Grain-Free for Horses?

of a horses diet is almost always hay which is recommended for gastrointestinal health but hay alone will not meet nutrient requirements. 
The Nutrient Requirements of Horses Sixth Revised Edition 2007 published by the National Research Council NRC has published recommendations to prevent nutritional deficiency. The six required nutrient categories for horses are water protein carbohydrates fat vitamins and minerals. A quality forage will typically meet the energy and protein requirements of most inactive or light riding horses but vitamins and minerals must be supplemented.
Carbohydrate Types 
It is impossible to remove all the carbohydrates from your horses daily ration and prior to trying to remove the starch and sugar it is critical to understand the different types of carbohydrates. As mentioned carbohydrates are one of the six essential nutrient classes for horses and are therefore required in the diet.
Carbohydrates are divided into two broad categories structural and nonstructural NSC. Structural carbohydrates are the fibrous portion of the plant hemicellulose cellulose polysaccharides therefore hay is a significant source of these. Structural carbohydrates will be the highest in mature and overly mature forages and lower in immature hay and pasture. In the foregut structural carbohydrates cannot be digested. The horse relies on the microbial fermentation in their hindgut to break down these nutrients into a usable energy form volatile fatty acids.
In contrast NSCs are the nonfibrous carbohydrates mono di oligosaccharides and polysaccharide starch. NSCs are the highest in cereal grains and will also be high in immature forages such as fresh pasture. This type of carbohydrate can be digested in the foregut by the digestive enzymes present. The energy from these carbohydrates can be absorbed by the horse earlier on in the digestive tract and therefore used immediately for energy.
Why is GrainFree Gaining Popularity? 
It is wellknown that horses do not thrive on high starch rations. When high NSC meals are fed the horse is unable to digest and absorb all the starch and sugar in the foregut and therefore some of it reaches the hindgut. When this occurs there is a disruption of the hindgut microbial population and an increased risk of gastrointestinal upset.
If your horse requires a low NSC diet testing your hay to ensure it is low in NSCs is critical for safety. Your hay analysis will also provide information on how much protein and energy the forage supplies. This is key information as you can then rely on