Yield and persistence of cool-season grasses under horse grazing

Cool-season grasses are the foundation of productive pastures throughout most of the United States; however many grasses have not been evaluated under horse (Equus caballus) grazing. The objectives were to evaluate forage yield and persistence of cool-season grasses under horse grazing. Four adult horses grazed Barolex tall fescue (Schedonorus phoenix Scop.) Hidden Valley meadow fescue (Schedonorus pratensis Huds.) Everett quackgrass (Elymus repens L.) Agassiz smooth bromegrass (Bromus inermis Leyss.) Fleet and Paddock meadow bromegrass (Bromus biebersteinii Roem. and Schult.) Marathon reed canarygrass (Phalaris arundinacea L.) Survivor perennial ryegrass (Lolium perenne L.) Winneton timothy (Phleum pretense L.) Ginger Kentucky bluegrass (Poa pratensis L.) Garrison creeping foxtail (Alopecurus arundinaceus Pior.) and Baridana orchardgrass (Dactylis glomerata L.). Horses grazed each month from May to October in 2010 and May to September in 2011. Orchardgrass meadow fescue Kentucky bluegrass and tall fescue were the most persistent grasses with ≥78% ground cover while timothy reed canarygrass smooth bromegrass and creeping foxtail were less persistent with ≤24% ground cover (P ≤ 0.0006) aft er 2 yr of rotational grazing. Orchardgrass produced the highest yield with ≥10.1 t ha^-1 while creeping foxtail smooth bromegrass and timothy produced the lowest yield with ≤8.7 t ha^-1 (P = 0.0001). The majority of yield for most grasses occurred during summer with summer months contributing 40 to 83% of the total yield in 2010 and 2011 respectively (P ≤ 0.0330). Planting orchardgrass meadow fescue tall fescue and Kentucky bluegrass should maximize forage persistence and yield in Midwest horse pastures.