Cattle Distribution on Mountain Rangeland in Northeastern Oregon

Abstract

Cattle grazing distribution patterns were studied directly through observation and indirectly through plant utilization during 3 summer grazing seasons under continuous and deferred-rotation grazing systems. Small riparian meadows were the most preferred plant communities. Meadows covered 3-S% of the total observation area but 24-47% of all cattle were observed in those plant communities. Logged forest communities ranked second in animal preference when availabR. Relatively open-m menziesii plant communities were the most preferred forested habitats. Deferred grazing equalized cattle use between logged areas and P. ponderosa-P. menziesii forests and increased cattle use of riparian meadows. Heavily forested sites were least preferred by cattle. Slope gradient was the only physical factor consistently associated with cattle grazing distribution. Water distribution was not correlated with grazing patterns in uplant plant communities. Multiple regression models could not predict grazing distribution patterns with useful precision. Proper distribution of livestock grazing is an integral part of effective range management. The goal of livestock distribution management is to gain maximum safe use over as wide an area as possible without causing serious damage to any portion within it. Mountain rangelands often exhibit complex combinations of topography, plant communities and successional stages, water distribution, and other habitat factors which create especially difficult grazing distribution problems. For instance, utilization may reach 75 to 80% on gently sloping drainages while steep slopes 150 m away receive 5% use or less (Phillips 1965). On a relatively small range unit of 690 ha in northern Utah, as much as 62% of the area received no use by cattle (Gonzalez 1964). A better understanding of the interactions between livestock behavior, natural habitat factors, and management factors should aid in developing more effective methods of livestock distribution. This paper reports on a 3-year study of cattle distribution behavior. The objective of the study was to evaluate the effects of several physical, biological, and managerial factors on the patterns of cattle use of mountain rangelands. Direct observation and forage utilization sampling were used to quantify grazing patterns of cattle under both continuous and deferred-rotation grazing schemes.