Repeatability of Rangeland Behavioral and Social Traits Derived from Gps Collars

Abstract The ability of an individual to cope with stressors in their environment is going to be paramount in the face of climate change. Rangeland livestock experience harsh conditions including heat and/or cold stress, water and feed restrictions and risk of predation. In extensive management systems, the ability to capture the capacity to cope with stressors of an individual in its environment is encumbered by remote locations with difficult terrain and no access to power or the internet. GPS collars can provide insights into individual land-use behavior, e.g., their impact on the environment or ability to cope with stressors, and social interactions, e.g., mothering ability. GPS collars (n = 112) developed at the University of Idaho were deployed on 57 ewes and 55 lambs (45 ewe-lamb pairs) in an extensive rangeland environment at the Great Basin Research and Extension Center in Eureka, NV. The collars recorded location data every 10 minutes from July 27th to August 18, 2022. Coordinate fixes were successfully recorded 67.11 ± 27.12% of the time and resulted in a kept record occurring every 60 ± 202 minutes. Of the ewe-lamb pair devices, 43 pairs contributed 801 ± 703 paired records (i.e., records that occurred within 5 minutes of each other). GPS coordinate locations, and their respective capture times, allow for the analysis of distance traveled, water usage, dispersion, and ewe-lamb distance. Distance traveled was analyzed on a daily basis with a weighted median distance imputed for all travel times that lasted more than 900 seconds. Dispersion was defined as the distance of an individual from the centroid of the flock in meters, and was transformed to a Z-score based on the position of individuals with GPS coordinates captured within 10 minutes of the measurement of the individual. Ewe-lamb pair distances were cube root transformed. Twin status, dam line, age, and day were fitted as fixed classes to estimate the repeatability of records for mature ewes. Repeatability estimates of daily distance traveled, daily water usage, and daily dispersion were 0.22 ± 0.05, 0.30 ± 0.06 and 0.10 ± 0.03, respectively. Daily ewe-lamb distances had a repeatability estimate of 0.45 ± 0.08. Day of recording was significant for daily distance traveled (P-value = 2.72×10-4) and water usage (P-value = 1.06×10-3). No other effects were significant in any of the models. In conclusion, PLF tools are an enabling technology that allow for passive data capture in remote locations. Our findings suggest that GPS collars can elucidate a variety of land use and social behavior traits that could serve as meaningful criteria for selection in extensive livestock production settings. Selection on these indicators of resilience may increase livestock productivity and welfare by increasing heat stress tolerance via the analysis of novel behavioral traits seen on extensive rangelands.