Social Associations and Dominance of Individuals in Small Herds of Cattle

Abstract

A series of 6 daylight observations was made each summer and again each winter over 2 years to map cattle distribution on a California foothill pasture. Sixty animals were used in the study with no animals appearing in. 1 observation series. During daylight hours, small herds of cows containing between 14 and 16 animals were scan-sampled and videotaped every 15 minutes. A global positioning system was used to record the position of the camera to aid in accurately locating individual animals. Animal locations and individual identifications were then entered into a geographic information system (GIS) by on-screen digitizing using color orthophotographs. Animal positions were determined to be within 5 m of their true location. Association software, ASSOC1, was used to analyze animal positions to determine cattle subgroups and herd units. This position-based grouping was compared with observation-based grouping by researchers. Direct observation also identified dominant herd members. Older animals, up to 16 years of age, were generally dominant over younger animals, and subgroups tended to be composed of animals of similar age. The size of naturally occurring subgroups was between 3 and 6 animals. Some animals exhibited independence in their actions and behaviors compared with subgroup members. ASSOC1 produced grouping results consistent with direct observations. However, accurate interpretation of the ASSOC1 results depended on direct observational data. ASSOC1 identified close association patterns in 3 of the observations that defined the dominant animals in the herd. Forage availability and thermoregulatory needs influenced the distance between associated subgroup members. Distance between animals decreased when animals sought shade in summer or shelter in winter. Computer analysis of spatial data from GPS collars may be able to determine the social structure and identify dominant animals in herd situations. Incorporating knowledge of cattle social behavior should improve management of cattle on the range.

Do Movement Patterns of GPS-Tracked Cattle on Extensive Rangelands Suggest Independence among Individuals?

“…As indicated by previous research [6,12,18], the software program ASSOC1 provides a valuable resource in determining association patterns and independence of GPS-tracked cattle based on the proportion of positions that animals are within a specified distance from one another. Greater resources, reduced costs, and increased opportunities to track livestock with GPS collars will continue to improve our understanding of livestock distribution and grazing behavior.…”

“…At smaller herd sizes, cattle tend to have greater associations compared to cattle within larger herds [12,14,44]. The smaller herd sizes at the CDRRC (i.e., 43 cows) and Evans Ranches (i.e., 37 cows) may have influenced associations of cattle based on a limited number of companions.…”

“…ASSOC1 has been used to assess spatio-temporal independence of GPS-or radio-telemetry tracked elk (Cervus elaphus [6,[21][22][23]), mule deer (Odocoileus hemionus [22,24]), and cattle (Bos spp. [12,18]). …”

“…In contrast, larger herds (i.e., 53 to 240 cows) tended to form into multiple groups with associations between dyads that were stronger than what would be expected from chance. Harris et al [12] found that small cattle herds grazing California rangelands, with 14 to 16 animals, were usually located within 50 to 125 m of each other. Bailey et al [4] used only one GPS-tracked cow to determine the distribution characteristics of herds of six animals because visual observations indicated that cattle were never more than 100 m from each other.…”

Prescribed fire effects on resource selection by cattle in mesic sagebrush steppe. Part 2: Mid-summer grazing

“…This level of dynamic interaction or association among individual collared cows seemed fairly typical based our combined experience on this and other rangeland types. Other researchers (e.g., Harris et al, 2007), however, have observed association among range cattle at levels perhaps high enough to restrict how resourceselection analyses are conducted.…”