FORAGE GROWTH AND STEER PERFORMANCE ON KENTUCKY BLUEGRASS VS SEQUENTIALLY GRAZED KENTUCKY BLUEGRASS SWITCHGRASS

In the north central USA, Kentucky bluegrass (Poa pratensis L.) pastur es often become semi-dormant with low forage supply in summer. The obj ective of this study was to determine the effectiveness of a cool-warm -cool season pasture system for improving animal performance in Wiscon sin compared with season-long stocking of Kentucky bluegrass pasture. The cool-warm-cool season pasture system consisted of Kentucky bluegra ss in the spring and fall with 'Blackwell' switchgrass (Panicum virgat um L.) over summer. The study was conducted in central Wisconsin in 19 90 and 1991. The cool-season grass pastures were on a soil predominant ly Roscommon muck (mixed, frigid Mallic Psammaquents) having 3% or les s slope. The warm-season grass pastures were on a soil predominantly N ewsom loamy sand (mixed, frigid Humaqueptic Psammaquent) with no slope and Okee loamy sand (loamy, mixed, mesic Arenic Hapludalf) with 2 to 6% slope. Experimental animals were Hereford x Angus x Charolais beef steers (Bos taurus) weighing approximately 550 lb at the initiation of the trial. There was no difference between the two grazing systems fo r season-long average daily gain (mean of 1.3 lb/d). Grain per acre wa s also similar for the sequential grazing system and the continuous Ke ntucky bluegrass pasture (mean of 92 lb/acre). In this experiment, no summer decline in forage production or beef steer performance occurred on season-long Kentucky bluegrass pasture. Sequential grazing of cool -warm-cool season grass pasture did not show any advantage over season -long Kentucky bluegrass pasture for increasing beef gain per acre or animal performance in central Wisconsin.