Evaluating the performance of alfalfa cultivars in rotationally grazed pastures

Abstract

Although alfalfa (Medicago sativa L.) is an important and reliable hay crop in eastern Canada, it is generally not considered suitable for pastures. However, local studies have shown that alfalfa is capable of superior yield in mixtures under rotational grazing. This study evaluates the performance of commercially available, locally adapted, hay-type alfalfa cultivars and new experimental, grazing-type alfalfa synthetics under hay and two rotationally grazed regimes. Ten alfalfa cultivars, including five hay-type and five grazing-type cultivars, were seeded with the timothy (Phleum pratense L.) cultivar, Richmond, in mixtures. The two pasture regimes consisted of grazing to low and high residual heights. Over two dry growing seasons, the pasture management with high residual grazing height was more productive than the low; on average lenient rotational grazing pressure (high residual heights) produced 20% higher yield than low residual heights. Alfalfa cultivars selected specifically for continuous grazing were not, on average, superior to those hay-type cultivars selected for general adaptability to soil and environmental conditions in Atlantic Canada. Differences among cultivars within alfalfa type were significant. Over 2 production years, mixtures containing the hay-type cultivar, Apica, and the grazing type, Alfagraze, produced more dry matter on average than three others in the study, regardless of management regime. Key words: Grazing height, cattle grazing