Effects of Strip Versus Continuous Grazing on Diet Parameters and Performance of Steers Grazing Eastern Oregon Native Flood Meadows

Abstract

Native flood meadows in the northwestern U.S. are typically managed for hay production. However, management for use by grazing livestock is receiving increased interest. Irrigation water is primarily supplied by surface runoff from snowmelt occurring at higher elevations surrounding the meadows. This experiment was conducted to compare strip (SG) and continuous grazing (CG) effects on livestock diet quality and subsequent performance. On May 1, groups of 20 steers (253 kg) were randomly allotted to two replicates of SG and CG treatment pastures (5.6ha each). Animals in SG pastures were confined by electric fence to an area large enough to provide approximately 65% utilization after a 5- to 7-d grazing period. Average strip size was .5 ha, and varied from .23 to 1.15ha. Herbage allowance was between 305 to 1131 kg/AU under CG, and 72 to 198 kg/AU for SG treatments, as measured on d 1 in each strip.Biweekly esophageal extrusa samples and total fecal collections showed that over the grazing season, average CP of extrusa samples from CG tended to be higher than SG (P = .14), at 13.9 and 10.9%, respectively. Crude protein declined signifi-cantly between May and September. Diet IVDDM varied between treatments (P = .07), at 64.6 and 60.7% on CG and SG, respectively. Grasses were more frequent in extrusa samples from SG than CG (P = .06), at 49 and 35%, respectively. Meadow foxtail was the most common grass on the meadows and was more frequent in SG extrusa samples (P = .05). Forage intake was similar (P = .42) for both treatments, at about 2.1% of body weight per day. Steers were weighed biweekly. Steer average daily gain was greater under CG (P = .09) (1.16 kg/day) than SG (.77 kg/day).