The objective of this study was to compare cow-calf proximity patterns of nursing Angus X Hereford (AH) and Raramuri Criollo (RC) cows in large Chihuahuan Desert pastures during the summers of 2016 and 2017. Eleven cow-calf pairs of each breed grazed two adjacent pastures (1190ha, 1165ha) separately in a crossover design, for 4 weeks per deployment. Within each breed, a group of randomly selected cows were fitted with GPS collars which recorded animal position at 10-min intervals. Proximity loggers configured to record number and duration of contact events (< 1m distance) were also fitted on a subset of cow-calf pairs. All calves were <2 weeks old at the onset of the study. Data from the dam’s proximity loggers were used for analysis. The effect of breed (AH vs. RC) on duration and number of contact events, as well as distance traveled, path sinuosity, velocity, area explored, and time spent resting, grazing and traveling by the dams was determined via ANOVA. All variables were calculated for four daily periods: Midnight to Sunrise (AmNight); Sunrise to Noon (AmDay); Noon to Sunset (PmDay); and Sunset to Midnight (PmNight). Breed (Pasture*year) was treated as the experimental unit and differences were declared significant at P = 0.05.  Number and duration of cow-calf contacts was highest during PmDay and lowest during AmNight and no breed-related differences were observed. RC cows traveled farther at higher velocities during AmNight, AmDay and PmDay and explored an area almost three times larger than the area explored by AH counterparts (152 vs. 57 ha). RC cows spent more time traveling during AmNight, AmDay and PmDay, more time grazing during AmNight and PmDay and less time resting during AmNight and PmDay than their AH counterparts. Our data suggest that RC calves impose fewer constraints on their dams’ grazing patterns compared to commonly-used British crossbreds when grazing the Chihuahuan Desert during summer.