Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/10/2005
Publication Date: 2/12/2006
Citation: Ganskopp, D.C., Johnson, M.D., George, M., Mcdougald, N.K., Harris, N. 2006. Group associations among GPS collared cattle [abstract]. Society for Range Management Meeting Abstracts. Paper No. 154.
Technical Abstract: Cows are known to have an innate grouping or allelomimetic tendency that causes them to form social units. We designed this study to develop techniques that could identify subgroups, determine unit size, and examine their spatial behavior. We tested association software (ASSOC1) that was programmed into the KRESS modeler. The software assigns animals to groups based on spatial proximity exceeding a temporal threshold. We placed GPS collars on small herds of cows at the San Joaquin Experimental Range in California during 2001. Herds were composed of twelve, randomly selected, mixed-aged cows. One herd (H1) was collared in July/August; two herds in separate range units (H2, H3)), were collared in December. Animal positions were recorded every 15 minutes over a period of 24 days. Three collars in H1 and two collars in H2 failed to obtain total coverage and were excluded from analysis. Using a temporal threshold of 67 percent and spatial increments of 5 meters, subgroup and herd groupings were determined out to radius of 150 meters around each animal. Closely associated animals were detected at 30 meters in H1 and 35 meters in H3. Associated animals were within these distances 72 percent of the time. Three to six animals formed the majority of subgroups delineated at distances from 60 to 150 meters in H1 and H2 with the number of members increasing at greater spatial distances. A subgroup of 6 animals was detected at 60 meters in H3 and the entire herd unit was delineated at 150 meters.