Do Young Calves Influence Movement Patterns of Nursing Raramuri Criollo Cows on Rangeland?

Abstract

We compared movement patterns of nursing versus non-nursing cows and characterized cow-calf proximity patterns over 2 years in two herds of Raramuri Criollo (RC) cattle that grazed either desert rangeland of southern New Mexico, United States, or woodlands of west-central Chihuahua, Mexico. At each site, 9−14 randomly selected mature cows were fitted with Global Positioning System (GPS) collars configured to record animal position at 5-min intervals. Four to five GPS-collared nursing cows and their calves were also fitted with proximity loggers that recorded initiation time and duration of dam-calf contact events (< 1 m logger-to-logger distance). All calves were < 2 wk old at the onset of the study. Collared animals grazed with a herd of 30 and 35 cows at the NM site and with 68 and 87 cows at the Chihuahua site in 2015 and 2016, respectively. Non-nursing RC cows exhibited straighter travel paths and explored larger daily areas than their nursing counterparts. However, nursing and non-nursing RC cows in this study traveled similar distances each day, moved at comparable velocities, spent similar amounts of time close to drinkers, and did not differ in daily time spent grazing, resting, or traveling. A higher number of cow-calf contact events occurred during day versus nighttime hours, but total day versus night contact time was similar. As calves became older, the number of both day and nighttime contact events, as well as dam-offspring contact time, decreased significantly. Relative to their calves, dams explored larger areas of the pasture each day; however, cow-calf contact events occurred throughout the entire area grazed by the dams including areas surrounding the drinkers. Cow-calf interactions of RC cows resembled those of a strong follower regardless of the grazing environment and differed from previously reported mother-offspring relations in mainstream British beef cattle breeds.