Influence of Cow Age on Grazing Distribution in a Mixed-Conifer Forest

Abstract

Optimal distribution of cattle on forested rangelands has long been a subject of concern specifically related to uniform and sustainable use of forage resources. Our objective was to determine if cow age influenced distribution and resource use on forested rangelands. This study was conducted from 1991 to 2001 at the US Department of Agriculture Starkey Experimental Forest and Range, northeastern Oregon, a mixed-conifer forested rangeland. We used 43 039 locations of cattle taken from 1 h prior to sunrise until 4 h after sunrise and 4 h prior to sundown until 1 h after sundown from 15 July to 30 August to evaluate cattle distribution patterns during peak foraging time. Cattle were grouped into four age classes: 2- and 3-yr-old cattle, 4- and 5-yr-old cattle, 6- and 7- yr-old cattle, and cattle > 8 yr old. All age classes preferred areas with gentler slopes (P < 0.05), westerly aspects (P < 0.05), farther from water (P < 0.05), and with greater forage production (P < 0.05) than pasture averages. Cattle older than 3 yr of age selected areas with less canopy closure (P < 0.05) than the mean value for the pasture. Young cows (< 4 yr old) selected lower elevations and steeper slopes than the oldest cows (P<0.05). In summary, cow age and correspondingly its experience directly influences distribution patterns and forage resource use of cattle at the Starkey Experimental Forest and Range.