Location: Range Management ResearchTitle: Characterizing the spatial and temporal activities of free-ranging cows from GPS data Author
|Estell, Richard - Rick|
Submitted to: The Rangeland Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2012
Publication Date: 6/1/2012
Publication URL: http://handle.nal.usda.gov/10113/57201
Citation: Anderson, D.M., Winters, C.D., Estell, R.E., Fredrickson, E.L., Dominec, M., Detweiler, C., Rus, D., James, D.K. 2012. Characterizing the spatial and temporal activities of free-ranging cows from GPS data. The Rangeland Journal. 34:149-161. Interpretive Summary: This research described how animal borne GPS devices set to record 1 s fixes can be used to identify standing, foraging and walking activites among free-ranging cows. The protocol requires characterizing the rate of cow travel obtained from GPS fixes with observational data recorded simultaneously while observing animals engauged in each of the three activities and using the rates of travel determined from these concurrent data to categorize consecutive GPS fixes recorded when observers were not present. This approach provides a 24-7 spatial and temporal profile of these three important cow behaviors. The procedure was evaluated on a small herd of cows in each of two years immedately before and following the abrupt weaning of their calves. Though cow travel increased significantly following weaning the most interesting aspect of these data reveal that subtle within day changes also take place and these behaviors would be missed with a less frequent fix rate. Furthermore, by using the GPS time stamp data together with the sun's angle with respect to the horizon the three behaviors were further characterized. This information should provides resource managers unique information to proactively manage cow dominated landscapes. The key to obtaining this type of management information is to use electronics that are robust and consistently reliable.
Technical Abstract: Electronic tracking provides a unique way to document animal behavior on a continuous basis. This manuscript describes how uncorrected 1 s GPS fixes can be used to characterize the rate of cow travel (m·s-1) into stationary, foraging and walking activities. Cows instrumented with GPS devices were observed; and the beginning and ending times of the above activities were recorded. Data were collected across a number of days and among a number of cows in order to calculate a mean travel rate for each activity. GPS data were also collected when observers were absent from the paddock and these data were then characterized into the three activities based on rate of travel determined between consecutive GPS fixes. The activities were further characterized within a 24 h period based on the sun’s angle with respect to the horizon. GPS data were analyzed from four cows (two in 2009 and two in 2011) and collected for four consecutive 24 h periods before weaning and seven similar time intervals following weaning. Weaning took place in March each year around mid-day when calves were between 223 and 234 days of age. These data suggest abrupt weaning caused cows to change their spatial and temporal behavior not only among but also within days. Overall cow travel increased (p = 0.0093) post-weaning with subtle within day behavioral changes. Further testing will be required to substantiate the biological implication of spatial and temporal cattle behavioral changes when developing optimum proactive husbandry practices for managing cow dominated landscapes.