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ARS Home » Pacific West Area » Boise, Idaho » Northwest Watershed Research Center » Research » Publications at this Location » Publication #92463
Title: LIVESTOCK GRAZING EFFECTS ON FORAGE QUALITY OF ELK WINTER RANGE

Author
item Clark, Pat
item KRUEGER, WILLIAM - OREGON STATE UNIVERSITY
item BRYANT, LARRY - USDA FOREST SERVICE
item THOMAS, DAVID - OREGON STATE UNIVERSITY

Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Carefully-managed livestock grazing has been suggested as a tool to improve the forage quality of graminoids on big game winter range, however, formal testing of this hypothesis has been done using hand clippers rather than livestock as the forage conditioning agent. We report winter crude protein, in vetro dry matter digestibility, and dry matter yield responses of blue- bunch wheatgrass (Agropyron spicatum (Pursh) Scribn. & Smith), Idaho fescu (festuca idahoensis Elmer), and elk sedge (Carex geyeri Boott) to late spring domestic sheep grazing. The study was conducted in 1993 and 1994 on a big game winter range in the Blue Mountains of northeastern Oregon. A sheep grazing treatment and a sheep exclusion treatment were applied to 20 ha plots at 3 sites on teh study area. Crude protein and in vitro dry mat- ter digestibility of bluebunch wheatgrass of grazed plots relative to un- grazed plots increased by as much as 1.7 percentage points and 7.6 percent- -age points, respectively. Grazing reduced dry matter yield of bluebunch wheatgrass by as much as 202.4kg ha-1. Crude protein of Idaho fescue in grazed plots was 2.6 percentage points greater than in ungrazed plots. Cru de protein, in vitro dry matter digestibility, and dry matter responses of elk sedge were inconsistent between years and this may be related to dif- ferences in sheep utilization between years. Forage quality improvements in bluebunch wheatgrass and Idaho fescue obtained by late spring sheep gra- zing in this study may be important to the foraging efficiency and nutri- tional status of wintering Rocky Mountain elk (cervus elaphus nelsoni Bailey). The effects of forage conditioning treatments on the winter for- age quality of elk sedge require further study.

Technical Abstract: Carefully-managed livestock grazing has been suggested as a tool to improve the forage quality of graminoids on big game winter range, however, formal testing of this hypothesis has been done using hand clippers rather than livestock as the forage conditioning agent. We report winter crude protein, in vitro dry matter digestibility, and dry matter yield responses of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. & Smith), Idaho fescue (Festuca idahoensis Elmer), and elk sedge (Carex geyeri Boott) to late spring domestic sheep grazing. The study was conducted in 1993 and 1994 on a big game winter range in the Blue Mountains of northeastern Oregon. A sheep grazing treatment and a sheep exclusion treatment were applied to 20 ha plots at 3 sites on the study area. Crude protein and in vitro dry matter digestibility of bluebunch wheatgrass of grazed plots relative to ungrazed plots increased by as much as 1.7 percentage points and 7.6 percentage points, respect-ively. Grazing reduced dry matter yield of bluebunch wheatgrass by as much as 202.4 kg ha-1. Crude protein of Idaho fescue in grazed plots was 2.6 percentage points greater than in ungrazed lots. Crude protein, in vitro dry matter digestibility, and dry matter responses of elk sedge were inconsistent between years and this may be related to differences in sheep utilization between years. Forage quality improvements in bluebunch wheatgrass and Idaho fescue obtained by late spring sheep grazing in this study may be important to the foraging efficiency and nutritional status of wintering Rocky Mountain elk (Cervus elaphus nelsoni Bailey). The effects of forage conditioning treatments on the winter forage quality of elk sedge require further study.