Plant Factors Affecting Forage Consumption by Horses

Information on factors affecting pasture intake is essential for predicting nutrient intake by grazing horses. Successful and economic feeding strategies depend on our ability to predict the amount of nutrients obtained by horses from pasture. In addition, understanding the factors that influence the palatability of pasture plants would enhance the ability of agronomists to develop suitable genotypes for horse pastures. This research will investigate whether forage chemical composition (specifically the nonstructural carbohydrate components) affects pasture intake by horses. A second hypothesis is that alkanes can be used as internal and external markers to estimate pasture intake by horses. Finally, this study will investigate whether the preference of horses for specific forage genotypes affects the ability of those genotypes to persist under intensive grazing. This will be a 3 year project. In years 1&2, existing grazing plots will be used to evaluate horse preferences in relation to forage chemical composition and forage persistence. Data from the first two years will be used to establish grazing areas of four cool season grasses that vary in palatability to horses. Also in the first two years, we will validate alkane methodology for determining dry matter intake by horses. In year 3, pasture intake by horses will be measured during the growing season in the established plots. The effect of forage chemical composition, as well as forage genotype, on total intake will be evaluated. This study will provide the first quantitative information on the relationship between forage chemical composition and intake by horses and will provide a basis for future studies.