Grazing behavior and production for cattle on differing late-season rangeland grazing systems with or without protein supplementation

Authors: SPRINKLE, JAMES - University Of Idaho; SAGERS, JOSEPH - University Of Idaho; HALL, JOHN - University Of Idaho; ELLISON, MELINDA - University Of Idaho; YELICH, JOEL - University Of Idaho; BRENNAN, JAMESON - South Dakota State University; Taylor, Joshua - Bret; LAMB, JAMES - Furst-Mcness Company

Submitted to: Translational Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 6/8/2019
Publication Date: 12/16/2019
Citation: Sprinkle, J.E., Sagers, J.K., Hall, J.B., Ellison, M.J., Yelich, J.V., Brennan, J.R., Taylor, J.B., Lamb, J.B. 2019. Grazing behavior and production for cattle on differing late-season rangeland grazing systems with or without protein supplementation. Translational Animal Science. 3(suppl. 1):1792-1796. https://doi.org/10.1093/tas/txz100.
DOI: https://doi.org/10.1093/tas/txz100

Interpretive Summary: Not required.

Technical Abstract: The objectives were to determine if Hereford x Angus cows on continuously or rotationally grazed late-season rangeland differed in BW (all cows) or altered grazing behavior {2-yr-old cows classified as either low- or high-residual feed intake (LRFI or HRFI)} when provided or excluded from a protein supplement (3.17 kg/cow fed once/wk) from mid-October to mid-December. Treatments included continuously grazed, control (CCON, n = 75); continuously grazed, supplemented (CTRT, n = 71); rotationally grazed, control (RCON, n = 73); and rotationally grazed, supplemented pastures (RTRT, n = 73). Three LRFI and 3 HRFI collared cows in each treatment were fitted with 3-axis accelerometers and global-positioning-system data loggers for 28 d in 2016 and 45 d in 2017. Grazing time (GT), resting time (RT), and walking time (WLK) were analyzed with a mixed model with pasture, RFI group, yr, RFI group x yr, and pasture x yr as fixed effects and cow within (RFI group x pasture) as the random effect. Daily travel distance (DTD) was analyzed by yr with a mixed model with pasture, date, RFI group, RFI group x pasture, and pasture x date as fixed effects with the same random effect. Weight was analyzed with pasture, yr, cow age, pasture x yr, pasture x cow age, cow age x yr, and pasture x cow age x yr as fixed effects and cow within pasture as the random effect. The CCON group lost (P < 0.05) BW (-1.0 ± 2.99 kg) while CTRT (23.5 ± 3.05 kg), RCON (9.9 ± 3.30 kg), and RTRT (16.7 ± 2.89 kg) gained BW, with RCON having less BW gain than CTRT (P < 0.05). Cattle did not alter GT by either RFI group or pasture (P > 0.10; approximately 10.5 h/d), though cattle in 2017 tended to reduce (P < 0.10) GT on the supplementation day 29% of the time and the day following supplementation 14% of the time. In 2017, CTRT cattle reduced (P < 0.05) WLK (2.3 ± 0.32 vs 3.2 ± 0.29 h/d) and increased (P < 0.05) RT (11.3 ± 0.34 vs 10.3 ± 0.30 h/d) when compared to CCON. Similarly, there was a tendency (P < 0.10) for LRFI cattle in 2017 to have less WLK (2.4 ± 0.23 vs 3.0 ± 0.20 h/d) and more RT (11.0 ± 0.24 vs 10.4 ± 0.22 h/d) than did HRFI. Cattle with reduced nutritional requirements rested more and walked less than did cattle with greater nutritional quality demands, which may be related to searching behavior.