|Mayeux Jr, Herman|
Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/11/2005
Publication Date: 6/21/2005
Citation: Northup, B.K., Phillips, W.A., Mayeux, H.S. 2005. A modified forage system for stocker production in the Southern Great Plains, U.S.A. [abstract]. Proceedings of the 20th International Grassland Congress, June 26-July 1, 2005, Dublin, Ireland. p. 469. Interpretive Summary: Many wheat farmers and stockmen in the Southern Great Plains put low-cost gain on yearling stocker cattle by grazing annual winter wheat in fall through spring, and warm-season grasses in summer. While widely used, this system has gaps in time when high quality forage is not available. In 2003-2004, we conducted a study to test how well two varieties of introduced perennial wheatgrasses ('Manska' intermediate and 'Jose' tall wheatgrasses) worked as large-scale replacements for winter wheat. We assigned 440 lb yearling stocker cattle to 5.0-acre pastures of winter wheat and the wheatgrasses in November and grazed until late-December. Cattle were then moved to other wheat pastures for winter grazing (December-February), and then returned (680 lb cattle) to their original pastures for spring grazing (till May 1 for wheat, June 1 for wheatgrasses). We found that establishment costs for wheatgrasses ($222/acre) were 2.3 times those of wheat ($94/acre). However, when divided over the planned pasture life (7 years), establishment costs were just 48% of total annual (establishment + maintenance) costs, and total annual costs of wheatgrasses were less ($68/acre) than wheat. Wheatgrasses supported a 23% increase in grazing days compared to wheat, and longer grazing periods (190 vs. 170 days). Cattle on wheatgrass produced 78% of the average daily gain of cattle on wheat, and lower total gains than wheat (480 vs. 499lb/ac). Wheatgrasses also had lower costs per pound of gain than wheat ($0.14/lb vs. $0.19/lb), which allowed these pastures to produce higher ($+17.40/ac) potential gross values of gains above pasture costs. Lower pasture costs and longer growing seasons could make introduced wheatgrasses useful parts of stocker grazing systems.
Technical Abstract: Putting low-cost gain on yearling cattle with forage is a key agricultural activity in the Southern Great Plains. However, the primary forage system [winter wheat (Triticum aesitivum) and warm-season grasses] has gaps when quality forage is unavailable. In 2002-2004, yearling stocker cattle were assigned to paddocks of wheat (n=9) and two wheatgrass (Thinopyrum intermedium, T. ponticum) varieties (n=18), to test the function of perennials as large-scale replacements for wheat. Cattle (200 kg) were assigned to paddocks in November and grazed till late-December (65 d), moved to other wheat paddocks for the winter (January through mid-March), and were then re-assigned to their original paddocks for spring grazing (36 d for wheat, 63 d for perennials). Carrying capacity and livestock weight gains were determined, and establishment and annual maintenance costs were used to compare sward performance between perennials and wheat for the fall and spring periods. Establishment costs of perennials ($549/ha) were 2.3 times that of wheat ($224/ha). However, when amortized over the planned stand life (7 y), establishment costs were only 47% of total annual costs (maintenance + establishment), which were lower ($167/ha) than costs for wheat. Wheatgrass paddocks supported a 23% increase in stocker grazing days, over longer (190 vs. 170d) grazing periods. Average daily gains for cattle on wheatgrasses were 76-81% of cattle grazing wheat, and generated lower total gains (538 vs. 559 kg/ha) than wheat. However, wheatgrass paddocks had lower costs of gain ($0.31/kg vs. $0.42/kg), which allowed the production of $43/ha in additional gross (not including animal production costs) potential value of gain above sward costs. Lower costs and extended grazing seasons could make introduced wheatgrasses viable components of stocker production systems.