Grass and hay should be a staple in equine diets, as horses evolved to forage for at least 16 hours every day. But not all owners have access to high-quality forage, and some are searching for ways to ensure their horses maximize energy and nutrient digestibility from every bite. Here’s some good news for those owners: Researchers in Mexico have shown that adding supplementary fibrolytic enzymes (which break down important components of forage) to horses’ diets could help maximize digestibility and, thus, nutrient utilization.

“To demonstrate that the enzymes cellulase and xylanase benefitted horses, we offered a basal diet of wheat bran, oat straw, and a commercial concentrate either with or without those enzymes,” explained Prof. Dr. A.Z.M. Salem, a professor and researcher at the Universidad Autónoma del Estado de México Faculty of Veterinary Medicine and Animal Science, in Toluca.

After 15 days, the study authors found mares supplemented with the enzymes consumed more forage and had a higher total nutrient intake compared to the control group, and supplemented mares had lower fecal coliform counts (from the bacterium Escherichia coli, which can cause diarrhea) and gas production than control horses. In addition, the team noted that horses receiving the enzyme supplement had an improved ability to digest dry matter.

“The addition of fibrolytic enzymes to low-quality forage, such as oat straw, appeared to improve feed intake and nutrient digestibility without negatively affecting the mares’ health,” the team concluded