Forage Nutritive Value, Yield and Preference of Alfalfa and Clover Under Horse Grazing.

Legumes have potential to provide high quality pasture, but are rarely grazed as monocultures. The objectives of this research were to evaluate forage nutritive value, yield, and preference of legumes under horse grazing. Research was conducted during 2014. Legumes were established on May 16 as monocultures in a randomized complete block design with four replicates. Four adult horses grazed eight alfalfa varieties varying in fall dormancy and grazing tolerance, one red clover variety, and one white clover variety. Legumes were measured for yield on July 1, August 5, and September 15 at the bud stage. Forage nutritive values were measured in September and horse preference was measured in August and September by visually assessing the percentage of forage removal on a scale of 0 (no grazing) to 100 (100% of legumes grazed). Horses had a greater preference for red clover (91%) compared to ‘Red Falcon’ (66%) and FD 4 alfalfa (65%; P=0.045).   Alfalfa varieties had similar forage yields (10.1 to 7.9 t/ha; P ≥ 0.05). Both clovers had yield ≤ 6.0 t/ha and were less than the highest yielding alfalfa variety (P < 0.0001).   Red clover had the greatest CP concentration (27%) compared to ‘Cutting Edge’ and ‘Red Falcon’ alfalfa (23%; P ≤ 0.0001). White clover had the greatest NSC concentration (20%), while red clover had the lowest (13%; P = 0.002). Red clover had the greatest NDF (39%) compared to ‘BlueJay HR’ and ‘401Z+’ alfalfa and white clover which had 31 to 33% NDF (P = 0.005). White clover had the greatest equine DE (2.71 Mcal/kg) compared to red clover which had the lowest (2.49 Mcal/kg; P < 0.002). However, all legumes exceed equine DE requirements for adult horses at maintenance. Clovers were preferred by grazing horses, but yielded less than alfalfa varieties.