Preference by horses for bedding pellets made from switchgrass (Panicum virgatum) straw1

The bedding system used for stalled horses can affect their health. This study examined the saponin concentration in switchgrass (Panicum virgatum) straw, and bedding pellets made from switchgrass straw. Further, this study determined the palatability of bedding pellets made from switchgrass straw and pine wood to horses. Saponins have been implicated in photosensitization in livestock, including horses. The average concentrations of the saponins dichotomin and protodioscin in switchgrass bales were 0.37 and 0.19 μg/g, respectively. The concentration of dichotomin decreased 38% from bales to the final pellets from a combination of environmental factors and dilution with other plant material. In the initial 8-d trial, horses were tested to determine their preference for (1) switchgrass straw bedding pellets, (2) Omolene horse feed, (3) alfalfa hay cubes, and (4) Equine Pine Pellet bedding. In a second 4-d trial, barley straw was substituted for Omolene. On each test day, the fasted horses were given 30 min to consume the feeds and bedding pellets. Horses preferred both alfalfa cubes and Omolene (consumption ≥99% of offered) and rejected (P < 0.05) both switchgrass bedding pellets and pine bedding pellets (≤0.6% of offered). When barley straw was substituted for Omolene in the second 4-d period, horses consumed a small amount of straw (6% of offered), and again horses rejected (P < 0.05; ≤0.2% of offered) both switchgrass and pine bedding pellets. This study suggests that the risk of intoxication from horses ingesting bedding pellets made with switchgrass straw is very low.