Protein Supplementation and Grazing Behavior for Cows on Differing Late-Season Rangeland Grazing Systems.

The objective was to determine if low- or high-residual feed intake (LRFI or HRFI, = 24 for each) Hereford × Angus cows on continuously or rotationally grazed rangeland altered their grazing behavior when provided a protein supplement in late autumn. Treatments included continuously grazed, control (CCON, = 12); continuously grazed, supplemented (CTRT, = 12); rotationally grazed, control (RCON, = 12); and rotationally grazed, supplemented pastures (RTRT, = 12). Cows in each treatment had grazing time (GT), resting time (RT), and walking time (WLK) measured for 2 years with accelerometers. Bite rate (BR) was also measured. Time distributions of GT and RT differed by year ( < 0.05), being influenced by colder temperatures in 2016. Cattle in 2016 spent more time grazing during early morning and late evening ( < 0.05) and rested more during the day ( < 0.05). In 2017, cattle in the CCON treatment walked more ( < 0.05) during early morning time periods than did the CTRT cattle, indicative of search grazing. All supplemented cattle had greater BR ( < 0.05) than control cattle in 2017. Cattle with increased nutritional demands alter grazing behavior in a compensatory fashion when grazing late-season rangelands.