|CHAFFIN, ROXANNE - University Of Missouri|
|SCHARF, BRAD - University Of Missouri|
|JOHNSON, JAY - University Of Missouri|
|BRYANT, JENNY - University Of Missouri|
|KISHORE, DEEPAN - University Of Missouri|
|EICHEN, PEGGY - University Of Missouri|
|Carroll, Jeffery - Jeff Carroll|
|Chase, Chadwick - Chad|
|SPIERS, DONALD - University Of Missouri|
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/25/2011
Publication Date: 8/11/2011
Citation: Chaffin, R., Scharf, B., Johnson, J., Bryant, J., Kishore, D., Eichen, P.A., Carroll, J.A., Chase, C.C., Coleman, S.W., Burdick, N.C., Spiers, D.E. 2011. A comparison of LPS-induced febrile responses across heat-tolerant and heat–sensitive Bos Taurus cattle in different thermal environments [abstract]. Journal of Animal Science. 89:M12(E-Suppl. 1).
Technical Abstract: Accurate detection of fever in cattle is an important step in maintaining health of a herd. There is little information on several fronts regarding the differences in febrile response to a lipopolysaccharide (LPS) challenge. These include differences in hot (HS) and thermoneutral (TN) environments and between heat-tolerant and heat–sensitive cattle. Likewise, there has been no comparison of febrile responses across different regions of the body. Eighteen month-old Angus (ANG; Missouri-derived; n=11; 306.7 +/- 25.87 Kg BW) and Romosinuano (RO; Florida-derived; n=10; 312.9 +/- 31.96 Kg BW) heifers were fitted with ruminal telemetric transmitters (Tru; SmartStock, Pawnee, OK), rectal temperature dataloggers (Tre; Reuter et al., JAS 88:3291), and vaginal temperature dataloggers (Tvg; HOBO, Onset, Bourne, MA). Animals were housed in separate stanchions in four temperature-controlled environmental chambers (Brody Environmental Center, University of Missouri). Ambient temperature was within cycling thermoneutral range (TN, 18.5-23.5 degrees C) for a one wk adjustment period, followed by an increase in two chambers to cycling heat stress level (HS, 18.5-38 degrees C) for another two wks. On Day 20 of study, an Escherichia coli (O111:B4; Sigma-Aldrich, St Louis, MO) LPS (0.5 micrograms/Kg BW) was administered intravenously to all heifers at approximately 1000 h. Although LPS effect on Tru showed no differences (P>0.05) across breed or environment, there was an approximate 1 degree C increase in HS animals within 5 h following injection. Tre increased by over 2.0 degree C within 5 h of injection, with higher values (~0.4 degree C; P<0.05) for ANG versus RO and HS versus TN. During HS, RO heifers appeared to exhibit the largest increase in Tre. Although Tvg increased by over 2 degree C 6 h post-LPS injection (P<0.05), there were no general breed or environment differences. These results show that there are regional differences in thermal response to LPS injection, with Tre providing the greater separation across breed and environment. Additional studies are needed to verify a heat-induced increase in the febrile response following an LPS challenge.