Relationships between beef cow daily distance travelled, age, size, hide color, foraging optimization, and grazing distribution

Abstract

Movement and foraging behavior can influence animal productivity. Free-ranging cattle incur a high energetic cost from walking, but individuals that move more may do so to access greater forage quality leading to increased weight gains and weaning weights. Understanding how movement rates correlate with preferred demographic and phenotypic traits can inform breeding programs and management decisions. Beef cattle size has steadily increased in North America over the past 50 years due to selection for growth traits, and concomitantly the proportion of black-hided cattle has also increased. Consequently, understanding how cattle size and color influence movement rates, and how they vary with production stages, is critical for managers to make breeding selection, supplementation, and grazing rotation decisions. To better understand beef cattle movement in the context of industry trends and production stages, we deployed GPS collars on Bos taurus beef cows across a heterogeneous northern USA Great Plains rangeland to test 6 hypotheses related to individual movement variation: First, daily distance travelled varies with production stage due to different nutritional and physiological demands of each stage; second, older cattle are more experienced with their surroundings and move more per day to optimize resource acquisition; third, larger framed cattle have less capability to traverse rangelands and move less per day; fourth, red cattle receive less solar energy and move more during colder periods; fifth, individuals with greater movement distances use areas with greater forage quality; and sixth, individuals with greater daily movement distances are more optimally distributed across the range. Daily distance travelled varied by production stage with the shortest mean distance occurring during late-gestation (2730.97, 2671.54–2790.40) and longest mean distance during breeding (3089.85, 3017.71–3161.99). Mean daily distance travelled increased by 42.71 m (95 % CI = 0.17–85.24) per day for every additional year of cow age. At 0 degrees Celsius, red cattle moved an estimated 2758.93 m (95 % CI = 2670.32–2847.54) compared to an estimated 2584.90 m (2500.68–2669.13) for black cattle. Daily distance travelled did not vary with cow frame size. Mean daily distance travelled was positively related to both the maximum normalized difference vegetation index (β = 0.643, SE = 0.027, P = 0.016) and instantaneous rate of green-up (β = 0.075, SE = 0.020, P < 0.001) values of areas used daily. Additionally, daily distance travelled increased by 18.18 m (95 % CI = 12.78–23.58) for each additional degree of maximum slope use, and 484.89 m (451.12–517.66) for each additional 1000 m maximum distance from water. Our work documents that cattle movement rates vary with production stage and provides evidence that black-hided cattle may be better adapted to northern latitudes. Furthermore, we show that increased daily movement is indeed related to the usage of areas providing greater forage quality forage and optimizing grazing distribution. Moreover, experience of older cattle can translate to increased daily movement but there appears to be no effect of frame size. Our results can inform adaptive decision making for beef cattle grazing in complex rangelands experiencing cold winters globally.