TY - JOUR
T1 - Grazing behavior and production characteristics among cows differing in residual feed intake while grazing late season Idaho rangeland
AU - Sprinkle, James E.
AU - Taylor, J. Bret
AU - Clark, Patrick E.
AU - Hall, John B.
AU - Strong, Nicole K.
AU - Roberts-Lew, Meghan C.
N1 - Funding Information:
This work was supported by the USDA National Institute of Food and Agriculture, Hatch project # 1010550. Mention of a proprietary product does not constitute a guarantee or warranty of the product by the Idaho Experiment Station, University of Idaho, USDA ARS US Sheep Experiment Station, or the authors and does not imply its approval to the exclusion of other products that may also be suitable. We wish to acknowledge Rob Laird, Boyd Leonard, and Jack Hensley for animal care and management and Mark Williams for project coordination. Conflict of interest statement. None declared.
Publisher Copyright:
© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: [email protected].
PY - 2020/1/2
Y1 - 2020/1/2
N2 - The objectives were to determine whether cows previously classified during a postweaning test as either low or high residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter grazing activity while consuming poor-quality forage. Thirty Hereford × Angus (LRFI = 16; HRFI = 14) 2-yr-old mid-to late-gestation cows (pregnant with second calf) grazed sagebrush steppe for 78 d beginning 29 September 2015. BW and BCS were collected before and after grazing. Five cows of each RFI classification were fitted with global positioning system (GPS) collars on 16 November 2015 with data collection commencing 3 d later and continuing for 25 d in a 323-ha pasture. The GPS units collected location coordinates every 2 min from which total daily travel distance (DTD) was calculated. Visual counts for bite rate were obtained from collared cows over 8 d. Coordinate data, daily bite rate, BW, and BCS were analyzed as repeated measures using a mixed model, which included RFI group, day, and RFI group × day as fixed effects and cow within RFI group as the random effect. Change in BW and BCS was analyzed by ANOVA with RFI group as the main effect. Cow BCS and BW differed for both day (P < 0.0001) and day × RFI (P < 0.05). Body condition was less (P < 0.05) in LRFI cows at the beginning (5.8 ± 0.13 vs. 6.2 ± 0.14 BCS), but similar (P = 0.67) to HRFI at the end of the study (4.6 ± 0.13 vs. 4.6 ± 0.14). BW among the RFI groups did not differ (P = 0.20) prior to going to range. However, BW-change and BCS-change differed (P < 0.05) between RFI groups. Not only did the LRFI cows lose less BW (-50.0 ± 5.41 kg vs.-66.6 ± 5.78 kg) over the trial, they also were less variable with respect to BW loss. Cows did not differ (P > 0.21) by RFI for DTD or bite rate, but day was significant (P < 0.0001) with cows increasing bite rate as the season of year progressed (55.2 ± 5.63 bites/min for day 4 vs. 84.8 ± 5.32 bites/min for day 21) and increasing DTD as snow storms occurred. Although LRFI cows were leaner than HRFI cows at the commencement of the project, they lost less BW in a late season rangeland environment.
AB - The objectives were to determine whether cows previously classified during a postweaning test as either low or high residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter grazing activity while consuming poor-quality forage. Thirty Hereford × Angus (LRFI = 16; HRFI = 14) 2-yr-old mid-to late-gestation cows (pregnant with second calf) grazed sagebrush steppe for 78 d beginning 29 September 2015. BW and BCS were collected before and after grazing. Five cows of each RFI classification were fitted with global positioning system (GPS) collars on 16 November 2015 with data collection commencing 3 d later and continuing for 25 d in a 323-ha pasture. The GPS units collected location coordinates every 2 min from which total daily travel distance (DTD) was calculated. Visual counts for bite rate were obtained from collared cows over 8 d. Coordinate data, daily bite rate, BW, and BCS were analyzed as repeated measures using a mixed model, which included RFI group, day, and RFI group × day as fixed effects and cow within RFI group as the random effect. Change in BW and BCS was analyzed by ANOVA with RFI group as the main effect. Cow BCS and BW differed for both day (P < 0.0001) and day × RFI (P < 0.05). Body condition was less (P < 0.05) in LRFI cows at the beginning (5.8 ± 0.13 vs. 6.2 ± 0.14 BCS), but similar (P = 0.67) to HRFI at the end of the study (4.6 ± 0.13 vs. 4.6 ± 0.14). BW among the RFI groups did not differ (P = 0.20) prior to going to range. However, BW-change and BCS-change differed (P < 0.05) between RFI groups. Not only did the LRFI cows lose less BW (-50.0 ± 5.41 kg vs.-66.6 ± 5.78 kg) over the trial, they also were less variable with respect to BW loss. Cows did not differ (P > 0.21) by RFI for DTD or bite rate, but day was significant (P < 0.0001) with cows increasing bite rate as the season of year progressed (55.2 ± 5.63 bites/min for day 4 vs. 84.8 ± 5.32 bites/min for day 21) and increasing DTD as snow storms occurred. Although LRFI cows were leaner than HRFI cows at the commencement of the project, they lost less BW in a late season rangeland environment.
KW - beef cattle
KW - global positioning system
KW - grazing behavior
KW - rangeland
KW - residual feed intake
UR - http://www.scopus.com/inward/record.url?scp=85078393833&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85078393833&partnerID=8YFLogxK
U2 - 10.1093/jas/skz371
DO - 10.1093/jas/skz371
M3 - Article
C2 - 31820799
AN - SCOPUS:85078393833
SN - 0021-8812
VL - 98
JO - Journal of animal science
JF - Journal of animal science
IS - 1
M1 - skz371
ER -