Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 27, 1998
Publication Date: N/A
Interpretive Summary: Cattle producers in the southeastern USA commonly plant cool-season annual grasses into bermudagrass to extend the grazing season with forage of high quality. A two-year grazing study was conducted with bermudagrass drill- planted with wheat and ryegrass to compare steer performance and forage nutritive value between continuous stocking, 3-paddock (10 days of grazing and 20 days of regrowth) and 11-paddock (2 days of grazing and 20 days of regrowth) rotational stocking systems. The pastures were grazed from early spring until late summer with varied stocking rates to maintain similar forage heights for continuous pastures and postgraze paddocks. Laboratory measurements of digestibility indicated that digestibilities were similar between continuous and the average taken over grazing periods for the two rotation systems. Split applications of nitrogen fertilizer resulted in crude protein being kept high and having minimal changes over grazing periods for the rotation systems. Average daily gain was similar among grazing treatments for cool-season annual grasses and bermudagrass. Higher stocking rates were accomplished with rotational stocking for cool-season annuals, which further resulted in the rotational stocking treatments having higher total liveweight gain per acre. Stocking rates and total liveweight gain per acre for bermudagrass were similar between continuous and rotational stocking. Results of the study indicated that rotational stocking can enhance steer production on wheat-ryegrass, but not on bermudagrass. Also, the more intensive 11-paddock system was not more productive than the 3-paddock system on either wheat-ryegrass or bermudagrass.
Technical Abstract: Considerable research has been conducted comparing animal performance between rotational and continuous stocking, but these grazing studies have been primarily with perennial grasses in monocultures or in mixture with legumes. A 2-yr study was conducted with bermudagrass (Cynodon dactylon [L.] Pers.) drill-planted with wheat (Triticum aestivum L.) and ryegrass (Lolium multiflorum Lam.) to compare steer performance and forage nutritive values between continuous stocking, 3-paddock low-intensity and 11-paddock high-intensity rotational stocking systems for both the cool- season annuals and warm-season perennial. In vitro DM digestibility (IVDMD) and crude protein (CP) were similar (P>0.10) between continuous stocking and averages of pregraze, midgraze, postgraze sample times for both rotation systems. There were decreases (P<0.05) of IVDMD over sample times within grazing periods for both rotation systems. Declines in IVDMD during the cool season (P<0.001) occurred between midgraze and postgraze sample times while decreases during the warm season (P<0.10) were detected throughout the grazing period. A distinct reduction in CP (P<0.10) during grazing periods was observed only for the cool season in 1994. Average daily gain was not affected (P>0.10) by the grazing treatments in either season. Higher stocking rates were achieved (P<0.01) with rotational stocking than with continuous stocking during the cool season, but not (P>0.10) during the warm season. Thus, there was higher (P<0.05) liveweight gain per acre with rotational stocking during the cool season, but not (P>0.10) during the warm season. Results of the study indicate that rotational stocking can enhance steer production on wheat-ryegrass, but not on bermudagrass.