|Title||Spatial and temporal free-ranging cow behaviour pre and post-weaning|
|Publication Type||Conference Paper|
|Year of Publication||2010|
|Authors||Anderson D.M., Winters C, Doniec M, Detweiler C., Rus D, Nolen B|
|Conference Name||4th Grazing Livestock Nutrition Conference|
|Conference Location||Estes Park, CO|
|ARIS Log Number||257426|
Global positioning system (GPS) technology can be used to study free-ranging cow behaviors. GPS equipment was deployed on each of ten cows ranging in age from 3 to 15 years in order to compare and contrast mean ± standard errors for pre- and post-weaning travel (m∙time-1) in two similar (≤ 433 ha) arid rangeland paddocks. Data were collected at a rate of one position fix per second between 12 March and 8 April 2009 for a total of 8.7 million raw GPS fixes across both paddocks. In addition, all 10 instrumented cows, 5 per paddock, were observed for a total of 32 h across 13 d and their behaviors were recorded on a minute by minute basis during daylight. The observational data were used to classify rate of travel (m∙min-1) into walking, foraging and stationary behaviors. The observed behavioral data were merged with the GPS data. Next the merged data were examined to classify the GPS data by path speed (m∙s-1). Intervals of 30 s, 60 s, 120 s and 180 s were evaluated to determine the optimum path speed sampling period to discriminate among walking, foraging and stationary behavior. The path speed associated with “stationary” was due to the inherent variability within the uncorrected GPS data used in this study. Regardless of interval chosen, three distinct peaks were observed. Within the ranges evaluated, longer sampling intervals (180 s) appeared to show better peak definition, especially for those peaks associated with foraging (0.10 m∙s-1) and “stationary” (0.03 m∙s-1) behaviors. Shorter sampling periods (30 s) produced smother curves having less distinct peaks, probably as a result of more samples. The fastest movement had a peak at 1.00 m∙s-1 and corresponded to periods when the cows were observed to be traveling between points on the landscape. A 1.00 m∙s-1 rate of travel is roughly 2.2 miles per hour, a speed used to manually gather these cows. Subsequent analyses were performed using 60 s sampling intervals as a compromise for well defined peaks and troughs, smoothness of the curve, and relatively high frequency counts at the high speed end of the distribution. Overall, mean cow travel increased post-weaning over 5 d in Paddock 10B from 1,428 ± 92.6 m∙d-1 to 1,955 ± 143.4 m∙d-1 and over 8 d post-weaning in Paddock 14A from 1,166 ± 105.8 m∙d-1 to 1,509 ± 92.0 m∙d-1. Mean travel in the two paddocks during foraging both pre- and post-weaning varied within a day but not in an identical manner even though the two paddocks were similar in size and topography. Among four 6 h time intervals foraging travel decreased following weaning between 0600 h (6 am) and noon and between 1800 h (6 pm) and midnight in both paddocks while travel associated with foraging increased between noon and 1800 h (6 pm) in both paddocks. Foraging travel between midnight and 0600 h (6 am) decreased in Paddock 10B following weaning (64 ± 5.6 m∙6h-1 vs 42 ± 4.4 m∙6h-1) but increased in Paddock 14A (24 ± 6.6 m∙6h-1 vs 60 ± 7.3 m∙6h-1) during this same time interval following weaning. Differences in foraging travel between midnight and 0600 h (6 am) in the two paddocks may have resulted from several factors including: the number of non-instrumented cows being different in the two paddocks, different weaning dates 13 d apart, and a different spatial distribution of cows within each paddock. Furthermore, GPS data were lost possibly due to battery failure. Only one 24 h period of data were lost from one cow in Paddock 10B (post-weaning) compared to loss of GPS data from two and three of the five cows for 24 h pre- and post-weaning, respectively, in Paddock 14A. Further data analysis evaluating tortuosity of travel (a metric that relates path speed or the summation of distances between each of 60 positions within a minute to displacement speed the distance between only the first position and the 60th position within a minute) appears promising to further characterize free-ranging cow travel. pg 192.