|Brauer, David - Dave|
Submitted to: Forage and Grazinglands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2004
Publication Date: 2/10/2005
Citation: Aiken, G.E., Looper, M.L., Tabler, S.F., Brauer, D.K. 2005. Supplementation with ground corn is cost effective for increasing weight gain of steers grazing bermudagrass. Forage and Grazinglands. http://www.plantmanagementnetwork.org/fg.
Interpretive Summary: Bermudagrass is extensively utilized for cattle grazing in the southeast U.S.A., but daily weight gains decline in the middle to late grazing season. This summer slump is partially due to reductions in digestible energy as the grass matures through the grazing season. Therefore, weight gains of beef calves on bermudagrass pasture could be increased by supplementing with a high-energy concentrate in the middle to late summer when forage energy deficits are most pronounced. It could also save time and labor expense if supplementation cab be done less frequently than daily without a drop in production. A grazing experiment, conducted with yearling steers on bermudagrass pasture, showed that daily weight gain per animal and total weight gain per acre were increased by supplementation with ground corn (2 lb/steer/day) for the entire grazing season than with supplementation in the later half of the grazing season. Furthermore, risk assessments indicated costs of additional weight gain for feeding the entire grazing season were below breakeven costs for a wide range of corn (90 to 100 dollars/ton) and cattle selling prices (0.60 to 1.00 dollars/lb). There also were no differences in yearling weight gain between 24 and 48 hour feeding intervals. Cattlemen that background calves on bermudagrass can cost effectively increase weight gain by feeding ground corn for the entire grazing season. Furthermore, cattle can be fed at 2 day intervals to reduce labor and time costs.
Technical Abstract: Bermudagrass (Cynodon dactylon L. Pers.) is widely managed for cattle grazing in the southeast U.S.A., but growth rates of stockers generally decline in the middle to late grazing season. Reduction in digestible energy of the grass in the late season has been implicated in this summer slump. A 2-yr experiment compared animal and pasture responses for grazing steers supplemented with ground corn (2 lb steer/d) over the whole grazing season (WGS), supplemented in the late grazing season (LGS), and with no supplementation (control). Two feeding intervals of 24 and 48 h also were compared for the WGS and LGS treatments. In vitro dry matter digestibility of bermudagrass declined throughout the grazing season in 2002 and during the first 80 d in 2001. Crude protein also declined but tended to increase to levels marginal to above animal requirements for growth following a second application of N fertilizer. Supplementation for WGS provided increased (P < 0.05) ADG and weight gain per acre compared to the control and LGS. Average daily gain and gain per acre did not differ (P > 0.10) between 24- and 48-h feeding intervals. Risk assessments of costs for additional ADG indicate that costs for WGS were lower (P < 0.05) than breakeven costs over a range of corn and cattle prices. Feeding ground corn to yearling steers grazing bermudagrass can cost effectively increase ADG if fed for the whole grazing season at a consumption rate of 2 lb./steer/d.