Many horse owners are showing an interest this harvest season in feeding oat hay to their horses. Simply put, oat hay is hay that is made from an oat crop not harvested for grain.

"Oat hay is not a commonly used forage in a horse ration," Bob Coleman, equine specialist for the University of Kentucky College of Agriculture, said. "However, it can be effective in nutrition programs for older horses."

Coleman recommends cutting oats when the grain is in the soft dough stage and the leaves and stems are still green.

"Oat hay at this stage of maturity will have an energy and protein content similar to grass hay," he said. "But the calcium content may be lower than you would expect from a grass hay and you may need to supplement that in the ration."

Oat hay harvested when the plant is more mature and only a small amount of grain remains in the forage has the nutritional value of straw, therefore, limiting use in horse feeding programs.

"The energy and protein content of good oat hay make it a suitable forage for mature horses at maintenance and early gestating mares," Coleman said. "The hay is palatable, however, horses still will selectively consume the grain and leaf portion of the hay leaving the stems."

Horse owners need to be aware of the potential for high nitrate levels in oat hay. Higher levels of nitrate may be present in oat hay if it was grown with high nitrogen fertilization or the plants have suffered the effects of drought. Either situation can cause the accumulation of nitrates in the feed. To prevent problems, Coleman recommends that horse owners test oat hay for nitrate levels to ensure the forage is safe. The level of nitrate in the horses total diet should not exceed 0.5 percent.

So, oat hay is useable for horse rations, but not all horse rations. Feeding oat hay should be restricted to mature horses and producers should make sure the hay quality meets nutritional requirements and is not too high in nitrate.