SRM AM19 Abstracts
Abstract Proceedings of the 72nd Society for Range Management International Meeting February 10-13 Minneapolis, Minnesota 1 A Comparison of Two Methods to Estimate Heifer Activity Using GPS and Accelerometer Data Fatima Continanza, New Mexico State University, Las Cruces, New Mexico Jennifer Muscha, USDA-ARS Fort Keogh, Miles City, Montana Mark Petersen, USDA-ARS, Miles City, Montana Andrew Roberts, USDA-ARS, Miles City, Montana Qixu Gong, New Mexico State University, Las Cruces, New Mexico Huiping Cao, New Mexico State University, Las Cruces, New Mexico Andrés Cibils, New Mexico State University, Las Cruces, New Mexico There is increasing interest in the use of low cost GPS units to monitor livestock movement and activity patterns on rangeland. Such devices seldom include movement sensors. On the other hand, 2- or 3-axes accelerometers included in several commercially available GPS units often yield activity data with low animal-to-animal consistency. Our objective was to compare two methods of estimating activity of rangeland heifers monitored with collars equipped with GPS and 2-axis accelerometers. The first method (VEL) involved classifying GPS points based on movement velocity thresholds. Resting was assumed when velocity < 2 m/min, velocities between 2-25 m/min were assumed to indicate grazing, and velocities > 25 m/min were classified as traveling. The second method (MOV) included a classification tree model that discriminated between resting, grazing, and traveling activities considering the distance between GPS points and both horizontal and vertical movement values recorded by a 2-axis accelerometer. Lotek 3300LR GPS collars were fitted randomly on heifers (18 days) in spring 2015 (n=20), 2016 (n=18), and 2017 (n=41).
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