Location: Livestock Issues Research
Title: Heat-tolerant versus heat-sensitive Bos taurus cattle: Influence of air temperature and breed on the acute phase response to a provocative immune challenge Authors
Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 12, 2013
Publication Date: September 16, 2013
Citation: Carroll, J.A., Sanchez, N.C., Chaffin, R., Chase, C.C., Coleman, S.W., Spiers, D.E. 2013. Heat-tolerant versus heat-sensitive Bos taurus cattle: Influence of air temperature and breed on the acute phase response to a provocative immune challenge. Domestic Animal Endocrinology. 45:163-169. Interpretive Summary: This research represents a collaborative effort of scientists from the Livestock Issues Research Unit, the SubTropical Agricultural Research Station, and the University of Missouri to determine the influence of breed on the immune response of cattle housed at two different air temperatures (thermal neutral and heat stress). Breed is understood to affect many aspects of production, including reproduction, growth, and immune function. Additionally, certain breeds of cattle are known to possess different traits, such as heat-tolerance. Specifically, the Romosinano breed is known for its longevity, docile temperament, and adaptation to tropical stressors. Therefore, we utilized two diverse Bos taurus breeds, Romosinuano (heat-tolerant) and Angus (heat-sensitive) to determine if their immune responses differed when housed at different air temperatures. Results from this study suggest that differences in the immune responses exist between the breeds when housed in a thermal neutral environment, and when housed in a heat stress environment. Specifically, Romosinuano heifers housed in a thermal neutral environment maintained lower rectal temperature in response to a pathogen compared to the Angus heifers. Additionally, differential, and sometimes opposite, pro-inflammatory cytokine responses were evident between breeds when housed at different air temperatures. These data sugges that differences in the immune responses between heat-tolerant and heat-sensitive breeds under different air temperatures exist, and these differences may aid at understanding the differences in productivity, disease resistance, and longevity among cattle breeds. These data will be of interest to scientists in the field of stress physiology and immunity, as well as cattle producers, and can be used to modify management practices in order to enhance cattle health and well-being.
Technical Abstract: 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.