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Heat-tolerant versus heat-sensitive Bos taurus cattle: Influence of air temperature and breed on the acute phase response to a provocative immune challenge

Carroll, J. A., Burdick Sanchez, N. C., Chaffin, R., Chase Jr., C. C., Coleman, S. W., Spiers, D. E.
Domestic animal endocrinology 2013 v.45 pp. 163
Angus, Romosinuano, air temperature, blood, body weight, catheters, cortisol, disease resistance, heat, heat stress, heat tolerance, heifers, interferon-gamma, interleukin-6, lipopolysaccharides, longevity, sampling, stanchions, tumor necrosis factor-alpha
The difference in the response of a heat-tolerant and a heat-sensitive Bos taurus breed to lipopolysaccharide (LPS) challenge when housed at different air temperatures (Ta) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kilograms body weight) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kilograms body weight) heifers were transported from the USDA-ARS SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in four temperature-controlled environmental chambers. Initially, Ta in the four chambers was cycling at thermoneutrality (TN; 18.5 to 23.5C) for a 1-week adjustment period, followed by an increase in two chambers to cycling heat stress (HS; 24 to 38C) for 2 weeks. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 microgram/kilogram body weight; 0 hour) and sickness behavior scores (SBS) were recorded and blood samples were collected at 0.5-hour intervals from -2 to 8 hours and again at 24 hours relative to LPS challenge at 0 hour. Serum was isolated and stored at -80C until analyzed for cortisol and cytokine concentrations. There was a tendency (P = 0.054) for a breed x Ta interaction in RT such that RO heifers housed at TN had the lowest RT compared to RO heifers housed at HS and ANG heifers at TN and HS following LPS challenge. In response to LPS, there was no difference in SBS between ANG and RO heifers when housed at TN (P = 0.62). However, RO heifers produced greater SBS compared to ANG 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 ANG heifers (P = 0.03). There was a breed by Ta interaction (P < 0.01) for tumor necrosis factor-alpha (TNF-alpha) concentration such that TNF-alpha was greater in RO heifers at TN, yet ANG heifers had greater TNF-alpha at HS. There was a tendency (P < 0.06) for a breed by Ta interaction for interleukin-6 (IL-6) concentrations such that RO heifers produced greater IL-6 at HS than all other heifers. There was a breed by Ta interaction for interferon-gamma (IFN-gamma; P < 0.01) concentrations such that IFN-gamma was greater in ANG heifers at TN than all other heifers. 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.