Reducing Winter Feeding Needs in Southern Arkansas Through the Use of Best Management Grazing Principles

Tuesday, July 22, 2014
Exhibit Hall AB (Kansas City Convention Center)
Brandon Stewart , University of Arkansas SWREC, Hope, AR
Paul Beck , University of Arkansas SWREC, Hope, AR
Landon Sullivan , University of Arkansas SWREC, Hope, AR
Michael Sims , University of Arkansas SWREC, Hope, AR
John Jennings , Department of Animal Science, University of Arkansas, Little Rock, AR
Abstract Text: Research is being conducted at the University of Arkansas Southwest Research and Extension Center in Hope, AR to determine the impacts of best management principles (BMPs) on production and winter feed requirements of spring calving cows (n = 72, BW = 547 ± 33.2 kg) grazing warm-season based pastures (n = 9, 4.7 ha pastures). The BMPs used include rotational grazing to improve pasture utilization; stockpiled bermudagrass, to extend grazing into the fall and early winter; and complementary cool-season annual grass plantings, to provide high quality forage in the spring. This research compares low management (CG, continuous grazing at a moderate stocking rate of 0.8 ha/cow) and intensive management at moderate (MR, 0.8 ha/cow) and high stocking rates (HR, 0.4 ha/cow). Stockpiling was managed by fertilization of 0.25 ha/cow of bermudagrass in early August with 168 kg ammonium nitrate/ha and deferring grazing until November. Pregnancy rate data were analyzed using the Chi-square test and cow performance data were analyzed by ANOVA using the mixed procedure of SAS (SAS Inst. Inc., Cary, NC). Stockpiled bermudagrass produced over 5,800 ± 500 kg forage DM/ha which was adequate to hold cows grazing these pastures until late February. During calving, from mid-February to mid-April, cows on MR and HR grazed cool-season annuals  and stockpiled bermudagrass or fed hay on alternating days. Cows on CG pastures were fed hay an average of 74 ± 7.3 d compared with 43 ± 7.3 d for HR and 0 for MR (P = 0.04). Pregnancy rates at weaning were similar (P = 0.99) across treatments averaging 85%. Growth performance of calves was reduced (P = 0.04) by both rotational grazing and increased stocking rate, with weaning weights of calves from CG (251 ± 9.1 kg) being greater than MR (222 ± 9.5 kg) which was greater than HR (212 ± 7.2 kg). However, total weaning weight per hectare was 68 and 90% greater (P= 0.01) for HR compared with CG and MR, respectively. With rotational stocking there was the opportunity to harvest excess forage as hay in both the moderate (9,418 kg/pasture) and high (2,206 kg/pasture). In this system every year will be different and flexibility of management will be key. Using rotational grazing, stockpiled bermudagrass, and complementary cool-season annual grasses can drastically reduce stored winter feed requirements and simultaneously increase carrying capacity and total net return.

Keywords: bermudagrass, cool-season annuals, cow calf, rotational grazing