Get reliable rangeland science

Feeding site selection is a critical part of livestock foraging that can constrain and/or increase choices available during diet selection. When livestock choose new feeding sites, vegetation and nutrient profiles can differ from previously visited sites. The objective of this study was to evaluate how terrain and corresponding heterogeneity may affect cattle feeding site selection patterns. Grazing patterns of mature cows were evaluated on 6 ranches located in Arizona, Montana and New Mexico. Eleven to 19 cows were tracked for 1 to 3 months at each ranch using global positioning system (GPS) collars. Positions were recorded at 10 or 15 minute intervals and used to identify where cows grazed during the early morning (0500 to 1000 hours). Pastures (336 to 9740 ha) at each ranch were divided into 7 to 9 sections (48 to 1082 ha) as an indicator of feeding sites. Classification was based on cattle density and topographical and vegetation types. Sequences of selected sections were evaluated using transition matrices. For all ranches, the sequence of section selection differed from what would be expected by chance indicating that the section selected on the following day depended on the section selected on the previous day. For ranches with relatively gentle terrain, cattle selected a different feeding site each day for about 70% of the tracking period. In contrast, cows at the ranch with the most diverse terrain stayed in the same feeding site for over 10 successive days for 42% of the tracking period. Smaller pastures with only mountainous terrain were intermediate. Cows grazing gentle topography alternate among feeding sites (sections in this study) more frequently than cows grazing in pastures with more rugged topography. This pattern could potentially help livestock mix forages and select a more diverse diet.