ARS | Publication request: Influence of heat stress on the immune response of Angus and Romosinuano heifers to an LPS challenge

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2011
Publication Date: June 25, 2012
Citation: Sanchez, N.C., Chaffin, R., Carroll, J.A., Chase, C.C., Coleman, S.W., Spiers, D.E. 2012. Influence of heat stress on the immune response of Angus and Romosinuano heifers to an LPS challenge [abstract]. Journal of Animal Science. 90:22(E-Suppl. 1).

Technical Abstract: The difference in the response of a heat tolerant and a heat sensitive breed to lipopolysaccharide (LPS) when housed at different air temperatures (Ta) was studied. Angus (AG; n=11; 306 +/-26 kg body wieght) and Romosinuano (RO; n=10; 313+/-32 kg body weight) heifers were transported from Florida to Missouri. Heifers were housed in stanchions in four temperature-controlled environmental chambers. Initially, Ta in four chambers was cycling at thermoneutrality (TN; 18.5 to 23.5 C) for a 1-week adjustment period, followed by an increase in two chambers to cycling heat stress (HS; 18.5 to 38 C) for 2 weeks. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On d 20, heifers were challenged with LPS (0.5 microgram/kg body weight; 0 hr) and blood samples were collected from -2 to 8 hr and at 24 hr relative to LPS challenge. Serum was isolated and stored at -80 C until analysis for cortisol and cytokine concentrations. Sickness behavior scores (SBS) were also measured. The AG heifers displayed greater RT than RO heifers when housed at either TN or HS temperatures (P<0.01), and produced a greater febrile response to LPS (P<0.01). In response to LPS, SBS tended to be greater in AG than RO when heifers were housed at TN (P=0.06). However, RO produced a greater SBS compared to AG heifers when housed at HS (P<0.01). The cortisol response to LPS was greater in TN than HS heifers (P<0.01) and were also greater in RO than AG heifers (P=0.03). There was a breed by Ta interaction (P<0.01) for tumor necrosis factor-alpha (TNFa) concentration such that TNFa was greater in RO heifers at TN, yet AG heifers had greater TNFa at HS. There was a tendency for a breed by Ta interaction for interleukin 6 (IL6) concentrations (P<0.06) such that RO heifers produced greater IL6 at HS. There was a breed by Ta interaction for interferon gamma (IFN-gamma; P<0.01) concentration such that IFN-gamma was greater in AG heifers at TN. These data demonstrate differences in the acute phase response between heat tolerant and heat sensitive breeds under different Ta which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds.