Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 5/21/2011
Publication Date: 7/10/2011
Citation: Richeson, J.T., Kegley, E.B., Powell, R.G., Schaut, R.G., Sacco, R.E., Ridpath, J.F. 2011. Weaning management of newly received beef calves with or without continuous exposure to a persistently infected bovine viral diarrhea virus pen mate: Effects on rectal temperature, peripheral blood leukocytes and serum proinflammatory cytokine concentrations [abstract]. Joint Annual Meeting American Dairy Science Association-American Society of Animal Science. Journal of Animal Science 89(E-Suppl. 1)/J. Dairy Sci. 94(E-Suppl.1). p. 157. Available: http://www.jtmtg.org/2011/abstracts/0157.PDF. Interpretive Summary:
Technical Abstract: Exposure to animals persistently infected (PI) with bovine viral diarrhea virus (BVDV) results in immunomodulation in cohorts. It is hypothesized that the extent of modulation differs for preconditioned (PC) vs. auction market (AM) cattle. Our objective was to compare immune responses of PC or AM calves in presence (PI) or absence (CON) of a PI-BVDV pen mate using a 2 × 2 factorial arrangement. Crossbred PC steers (n = 27) from a single ranch-origin were selected randomly, weaned, dewormed, vaccinated, tested for PI-BVDV, and kept on the ranch for 61 d. Subsequently, PC steers were transported to a stocker receiving unit (RU), weighed (282 ± 1.6 kg), stratified by d -1 BW, and assigned randomly to treatment (PCPI or PCCON) with no additional processing. Simultaneously, crossbred AM calves (n = 27) were assembled from regional auction markets and delivered to the RU 24 h before PC arrival. The AM calves were weighed (268 ± 2.3 kg), stratified by gender and d -1 BW, processed under the same regime used for PC steers at their origin ranch except bull calves were castrated, then assigned randomly to treatment (AMPI or AMCON). Treatment pens (50 m × 15 m) were arranged spatially so that PI did not have fence-line contact with CON. For cytokine and hemagram analyses, serum or whole blood was analyzed from d 0, 1, 3, 5 (hemagram only), 7, and 14. In AM calves, RT increased (P < 0.001) sharply on d 1. Exposure to PI cohort decreased (P = 0.01) the percentage of neutrophils, and increased (P = 0.02) percentage lymphocytes resulting in a tendency (P = 0.07) for a decreased neutrophil:lymphocyte ratio. Serum concentrations of TNF-alpha tended to increase (P = 0.09) for PI cohort. Interferon-gamma concentrations on d 7 and 14, IL-6 concentrations on d 14, and platelets on d 7 were greatest for AMPI (P less than or equal to 0.05). Results indicate weaning management and PI exposure alter the immune status of newly received calves. These effects may be additive because alterations were greatest for AMPI.