The normal requirement of roughage food for a horse is determined in relation to its body weight. Ideally speaking, a horse should get 1.5 percent to 2 percent of its body weight in roughage a day. But ideal situations are rare and as such it should be ensured that the animal gets a minimum of one percent of its body weight.
As in the case of the human diet, a higher percent of fiber content is required for horses. This is to keep the normal function of the digestive system working.
Roughages are a vital component in the diet of a horse including hay and pasture feeding, also. It is the source of necessary digestive energy, protein, and a small percentage of vitamins and minerals. The total requirement of food per day for an average animal is estimated at around 3 percent of the body weight of the animal. However the suggested percentage cannot be applied without consideration of a few basic facts. The feed needs to be adjusted based on the grain content in the food, the stage of growth of the animal, lactation, and the volume of work besides the expected body condition.
As already explained, the term roughage means high content fiber feed with an expected minimum fiber content of not less than 18 percent in crude form. Though hay and pasture are the normal roughage foods, there are many other alternate feeds that can be effectively used to replace both hay and pasture feed.
It is quite normal for horse owners to compromise on their hay and pasture feed supply in the daily diet of their horse, especially during a period of severe drought when they become too expensive. In such situations they may either be replaced completely or their quantity curtailed. It is in this context that the relevance of grains with moderate levels of fiber content comes into the picture. It is expected that such alternate feed contain eleven to fifteen percent of fiber. It should be remembered that such low fiber content cannot replace the hay and pasture benefits completely, but the amount of hay can be reduced successfully. The change in the feed may not be done immediately but should be done gradually. One needs to ensure that the horse gets at least one percent of its body weight in roughage per day and that the remaining portion is filled by the required quantity of moderate fiber feeds.
Though it has been stated earlier that a horse ideally requires one to two percent of their body weight as roughage in the daily feed, the same cannot be applied uniform for all type of horses. As per the standard prescribed by the nutrient requirement of horses, a normal mature idle horse may require roughage of 1.5 to 2 percent of its body weight. In the case of working horses though, it all depends on the intensity of work on an average day and can be taken as one to three percent. A mare, either in late gestation or lactation, may be seen as a work horse for the purpose of feed content, while weanling and yearling requires comparatively lesser quantity of roughage.
Having seen the importance of roughage in the diet of a horse, here are some of the alternate feed that can either partially or fully replace for the hay and pasture feeding. Alfalfa hay is a good supplement for the hay and the pasture feed in this category because it contains higher protein and calcium and less quantity would suffice. Grass hay and the Bermuda grass hay are also complete supplements for the normal hay and pasture feeding. Millet hay has less nutrient value when compared to other grass hays. This has a laxative effect when exclusively fed as roughage however, so owners should be attentive.
Other feed substitutes for roughage in full is sorghum grass, although it is not recommended because of its bad effect on the health of the animals and studies showing it leading to neurological problems. The other major supplements are haylage, oat hay, straw, beet pulp, soy hulls, alfalfa hay, Bermuda grass hay, and millet hay. These can be successfully used as a roughage substitute. Besides the above there are other sources of moderate fiber feeds that can be used as partial substitute for hay and pasture feeding in the horse feed, like rice, bran, wheat, bran, and oats.