Native grasses, bermudagrass and small grains are the most-often-grazed forages in the southern Great Plains. When used for direct grazing in this region, alfalfa has the potential to produce high animal gains and improve the seasonal distribution of high-quality forage during the spring through summer months. Grazing-tolerant alfalfa cultivars are also now available in different fall dormancy groups, which should help with this approach.
In 2001, Mary Sledge, Andy Hopkins and I (Forage Improvement Division), along with Hugh Aljoe (Agricultural Division), began a study to evaluate the potential of grazing alfalfa in the southern Great Plains region. The effect of two grazing strategies continuous grazing beginning in April or May of each year with either an August grazing (AG) or an August rest (AR) period on overall animal gain, as well as persistence of grazing-tolerant and hay-type alfalfa cultivars, were the main treatments evaluated.
Grazing treatments did not have a significant effect on stand persistence of grazing-tolerant cultivars such as "Alfagraze," but "Magnum V," an adaptive, hay-type cultivar, showed a 17 percent reduction in AG when compared to AR. The AG treatment also resulted in lower forage allowances for all cultivars, especially during the last two grazing years (see Table 1). Animal gains were good overall (three-year averages of 2.0 to 2.2 lbs. per day and total gains of 341 to 382 lbs. per acre) (Table 1). Average daily gains were higher for the AR treatment, but total per acre gains were higher for the AG treatment (Table 1).
Two important management considerations were demonstrated in these studies. First, the better stand survival of the grazing-tolerant cultivars across both grazing treatments confirms the positive value of the grazing tolerance trait found in cultivars such as Alfagraze to provide better stand survival in aggressively grazed areas. Second, animal gains on continuously grazed alfalfa during the spring-summer period are high and sustainable in the region, but producers may experience loss of future yield, daily gains and stand survival for not resting stands during the August period.
There also will be a new Alfagraze cultivar on the market in 2006 that contains improved pest resistance and the Roundup Ready® (RR) gene to allow use of Roundup® (glyphosate) herbicide for weed control under intensive grazing. It will be sold under the name "Alfagraze 300 RR." So far, we are recording good hay yields and grazing persistence for this cultivar in the Noble Research Institute trials.