Location: Livestock Issues ResearchTitle: Effects of feed supplementation and the method of weaning on the physiology and performance of beef calves Author
|Carroll, Jeffery - Jeff Carroll|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/11/2010
Publication Date: 10/11/2010
Citation: Campistol, C., Kattesh, H.G., Waller, J.C., Rawls, E.L., Pighetti, G.M., Carroll, J.A. 2010. Effects of feed supplementation and the method of weaning on the physiology and performance of beef calves [abstract]. 2010 American Society of Animal Science Meeting, July 11-15, 2010, Denver, CO. Journal of Animal Science. 88(E-Supplement 2):T273. Interpretive Summary:
Technical Abstract: A study was conducted to investigate growth performance and physiological measures of stress in pre- and post-weaned beef calves provided a grain supplement and weaned by fenceline or total separation. Angus steer calves (n = 48; 312.2 ± 27.9 kg), housed on pasture with their dams, were blocked by initial BW and assigned randomly on d 0 to be hand-fed a grain supplement (YS; 4.5 kg/head/d) or no supplement (NS) for 7 d. On d 7, calves (12 NS and 12 YS/group) were weaned by fenceline (Group 1) or total separation to a distant pasture (Group 2). On d 14, Group 1 calves were moved to a pasture lot adjoining Group 2. All calves were weighed and bled on d 0, 7, 10, 14, and 21, and provided access to the grain supplement on d 7-21. Blood was analyzed for plasma cortisol (CORT) and interferon-gamma (IFN) concentration, hematocrit (Hct), red blood cell (RBC) and white blood cell (WBC) total count, and neutrophil:lymphocyte ratio (N:L). By d 7, BW increased (P < 0.001) and RBC and IFN decreased (P < 0.001) in all calves. However, NS exhibited lower (P < 0.005) N:L (0.16 vs. 0.27 ± 0.03) and CORT (74.5 vs. 98.4 ± 7.2 nmol/L) compared to YS calves. By d 10, Group 2 steers experienced a reduction (P < 0.001) in BW compared to animals in Group 1, which was more pronounced in the NS calves. Measures for RBC, WBC, IFN and N:L increased (P < 0.01) in all calves within 3 d following weaning. Compared to NS, both Hct and CORT for YS calves decreased (P < 0.01) over this same period. From d 14-21, Hct decreased (P < 0.01) and IFN increased (P < 0.001). These results suggest that providing a grain supplement beginning 7 d prior to weaning may reduce BW loss and temper the animals stress response due to weaning.