|Falkenberg, Shollie - Mississippi State University|
|Carroll, Jeffery - Jeff Carroll|
|Ballou, Michael - Texas Tech University|
|Sartin, James - Auburn University|
|Buntyn, Joseph - Mississippi State University|
|Kahl, Stanislaw - Stass|
|Schmidt, Ty - Mississippi State University|
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/25/2011
Publication Date: 8/11/2011
Citation: Falkenberg, S.M., Carroll, J.A., Ballou, M.A., Sartin, J.L., Buntyn, J.O., Elsasser, T.H., Kahl, S., Schmidt, T.B. 2011. Alterations in the somatotrophic axis during a dual stress and M. haemolytica challenge in beef steers [abstract]. Journal of Animal Science. 89:A-399(E-Suppl. 1).
Technical Abstract: The objective of this trial was to characterize the potential impact of individual and multiple stressors prior to, simultaneously, and post M. haemolytica challenge on the somatotrophic axis. Forty-eight vaccinated beef steers (207.7 ± 22.1 kg BW) were randomly assigned to 1 of 8 treatments (trt). Treatments consisted of steers that received M. haemolytica (Mhae; given at 0 h for all 8 trts) and corticotrophin releasing hormone (CRH) + arginine vasopressin (AVP) in tandem as the stressor (Stress) administered prior to, simultaneously, or after the Mhae challenge. The 8 trt were: 1) Mhae only; 2) Stress at -7 h + Mhae; 3) Stress at 0 h + Mhae; 4) Mhae followed by Stress at 7 h; 5) Stress at -7 h and 0 h + Mhae; 6) Stress at -7 h and 7 h + Mhae; 7) Stress at 0 h and 7 h + Mhae; and 8) Stress at -7 h, 0 h and 7 h + Mhae. Steers were fitted with jugular catheters and rectal temperature (RT) probes on d -3, moved to stanchions, given a day to acclimate (d -2), baseline samples obtained on d -1, and the challenge was given on d 0. There were trt x time interactions or trt effects (p<0.05) observed for cortisol (CORT), growth hormone (GH), insulin-like growth factor-I (IGF-I), and RT. Differences were observed (p>0.05) in overall GH and IGF-I as well as concentrations prior to the Mhae challenge for trts that received multiple Stress challenges or Stress during and after the Mhae challenge. No differences were observed (p>0.05) for change in GH and IGF-I concentrations after the Mhae challenge. Furthermore, no differences were observed (p>0.05) in GH and IGF-I for trts that did not receive any Stress or Stress trt prior to the Mhae challenge. The results indicate the Mhae challenge altered GH and IGF-I in vaccinated calves regardless of the timing associated with the applied stress. However, the data also suggest that stressors can impact overall GH and IGF-I concentrations when stressors occur during and after the Mhae challenge.