Location: Livestock Issues ResearchTitle: Alterations in the somatotrophic axis during an infectious bovine rhinotracheitis viral (IBRV) challenge in beef steers 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: Falkenberg, S., Schmidt, T., Keisler, D., Sartin, J., Buntyn, J., Carroll, J.A. 2010. Alterations in the somatotrophic axis during an infectious bovine rhinotracheitis viral (IBRV) challenge in beef steers [abstract]. 2010 American Society of Animal Science Meeting, July 11-15, 2010, Denver, CO. Journal of Animal Science. 88(E-Supplement 2):771. Interpretive Summary:
Technical Abstract: To evaluate the effects IBRV has on immunological and physiological parameters of cattle, 12 Angus crossbred steers (228.82 ± 22.15 kg) were randomly assigned to either a Control group or an IBRV challenged group. Prior to the challenge steers were fitted with an indwelling rectal probe, BW were recorded, and a blood sample was obtained. On d 0, IBRV steers received an intra-nasal dose of IBRV (2 ml/nostril; Cooper strain, 1 X 10 exp 6-7 PFU) and Control steers received an intra-nasal dose of saline (2 ml/nostril). After the IBRV, steers were returned to their isolated paddocks for approximately 73 h. IBRV steers were placed in a paddock that was isolated from the Control cattle as well as all other cattle located on the research farm. During the first 48 h post-challenge, blood was collected via a single venipuncture of the jugular vein. At 72 h post-challenge steers were fitted with temporary indwelling jugular catheters, and then moved to individual metabolism stanchions. Blood samples were intensively collected on d 4, 5, 6, 7, and 8 post-challenge. IBRV steers had elevated rectal temperatures (p < 0.05) as compared to Control steers starting on d 1, returning to baseline on approximately d 6. Serum was analyzed for interleukin-1 beta (IL-1), IL-2, IL-4, IL-6, interferon-gamma (IFN), tumor necrosis factor-alpha (TNF), growth hormone (GH), insulin-like growth factor-1 (IGF-1) and cortisol. The response patterns for cortisol, IFN and GH all followed a similar pattern in IBRV steers. Cortisol, IFN, and GH increased in IBRV animals as compared to Control steers (p < 0.05) starting on approximately d 2, peaking on d 4, and tapering off on d 6. While GH did increase and there was a difference (p < 0.05) in GH concentrations between the IBRV and Control steers, IGF concentrations did not differ between the 2 groups. While the objective of this trial was to identify the cytokine response following IBRV exposure, and the impact on the somatotrophic axis, our data revealed alterations in the somatrotrophic axis that were not associated with detectable increases in circulating concentrations of pro-inflammatory cytokines. We hypothesize that the low dose of the virus used in the present study, while sufficient to elicit a febrile response, it did not result in the calves becoming septicemic which would explain the lack of a detectable pro-inflammatory cytokine response.