Submitted to: Forage and Grazinglands
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/7/2012
Publication Date: 3/1/2013
Publication URL: http://handle.nal.usda.gov/10113/55842
Citation: Coffey, K.P., Montgomery, T., Coblentz, W.K., Francis, P.B., Whitworth, W.A., Bryant, K.J. 2013. Performance by heifers grazing sod-seeded cool-season annuals seeded on different dates using two tillage intensities. Forage and Grazinglands. DOI: 10.1094/FG-2013-0226-01-RS. Interpretive Summary: When winter annuals such as wheat or rye are sod-seeded (no tillage) into grass pastures, they provide high-quality forage for wintering beef calves; however, forage production following sod-seeding normally lags behind that of winter annuals established following conventional clean-tillage methods. As a result, the initiation of grazing is delayed, and hay often is needed to supplement sod-seeded pastures. Throughout the southeastern US, typical target dates for sod-seeding are timed to occur after the base sod of bermudagrass enters fall/winter dormancy (late October to mid-November); this recommendation is designed to limit competition from the base sod of bermudagrass. It is possible that greater sod disturbance coupled with earlier seeding dates may increase fall forage production from sod-seeded winter annuals, thereby increasing grazing days during the fall and reducing the time fall-weaned calves must be maintained on other feedstuffs. To evaluate this premise, soft-red winter wheat and annual ryegrass were overseeded into primarily bermudagrass pastures during either early September or mid-October. Before seeding occurred, the base sod was disturbed with either light or moderate disking (tillage). Pastures were grazed through the winter by replacement beef heifers that had been weaned from their mothers in early October. Over the 3-year study, early-September establishment allowed grazing to be initiated 17 days sooner than observed for the later seeding date, thereby saving approximately 165 lbs of supplemental hay per heifer; additionally, weight gains were largely unaffected. Because of the high variability associated with early-fall weather patterns throughout the southeastern US, as well as the minimal differences observed in total animal performance, producers might be advised to split their pasture acreage and seed some in early fall, as well as some in later fall, as a hedge against inadequate forage supplies.
Technical Abstract: A total of 120 Gelbvieh x Angus crossbred heifers (552'2.5 lb initial BW) grazed pastures of common bermudagrass [Cynodon dactylon (L.) Pers.] overseeded with wheat (Triticum aestivum L.) and annual ryegrass (Lolium multiflorum Lam.) for a 3-year study to compare the effect of seeding dates and tillage intensities on heifer growth performance. Half of the pastures were seeded in early September (Early) and half in mid-October (Late). Within seeding date, half of the pastures were disked once (1x) and half were disked twice (2x) before seeding. Grazing began when forage mass reached approximately 2000 lb/acre and continued through May 11, 2002 (year 1), April 25, 2003 (year 2), and May 10, 2004 (year 3). Forage mass was greater (P < 0.05) from Early than from Late seeded pastures for 2 of the first 3 months of grazing resulting in 17 d earlier grazing initiation (P < 0.05) and approximately 165 lb less (P < 0.05) hay fed per heifer. Total body weight gain, or gain while grazing winter annuals, did not differ (P = 0.50) between seeding dates or tillage intensities. Therefore, producers with bermudagrass pastures may have considerable flexibility in their decisions as to when to seed annual forages and to what level they till their sod depending upon how soon they need available forage.