85  Utilizing cover crops in an equine grazing system

Cover crops are commonly used to provide soil cover and can extend the grazing season, but have not been explored in horse pastures. The objectives of this research were to evaluate yield, forage nutritive value, and horse preference of annual ryegrass (Lolium multiflorum L.), winter rye (Secale cereale L.), berseem clover (Trifolium alexandrinum L.), purple top turnip (Brassica rapa ssp. rapa L.), and daikon radish (Raphanus sativus ssp. longipinnatus L.) under horse grazing in the fall. We hypothesized that grasses and clover would be more suitable cover crops for horse pastures compared with turnip and radish. Cover crops were seeded in monoculture and mixtures in August 2018 and 2019 as a randomized complete block with 4 replicates and grazed by 4 adult horses. Horses grazed 2 replicates per day for 4 h. Grazing occurred in October 2018 and in both September and October 2019. Before grazing, forages were sampled and weighed to determine herbage and root yield and nutritive value was evaluated using wet chemistry. After grazing, forages were visually assessed for preference based on percentage of removal on a scale of 0 to 100%. Data were analyzed using an ANOVA and linear regression; significance was set at P < 0.05. Berseem clover was the lowest yielding forage (P < 0.0001). Yield of annual ryegrass, winter rye, berseem clover, turnip and radish averaged 2,293, 2,287, 763, 4,252, and 4,095 kg ha−1, respectively. All forages met digestible energy (>2.17 Mcal kg−1) and crude protein (>19%) requirements for adult horses at maintenance. Berseem clover was most preferred (>73% removal) while turnip and radish were the least preferred (<19% removal; P < 0.0001). No adverse health effects were observed while grazing cover crops during this short grazing period. Placing a priority on preference, berseem clover, annual ryegrass, and winter rye appear to be suitable cover crops to extend the grazing season in horse pastures.