Acute immunological and metabolic responses of beef heifers administered transdermal flunixin meglumine at various times relative to a respiratory disease challenge

Authors: WORD, ALYSSA - Texas Tech University; Broadway, Paul; Sanchez, Nicole; HUTCHESON, JOHN - Merck Animal Health; ELLIS, GUY - Merck Animal Health; HOLLAND, BEN - Cactus Feeders, Inc; BALLOU, MICHAEL - Texas Tech University; Carroll, Jeffery - Jeff Carroll

Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2019
Publication Date: 3/11/2020
Citation: Word, A.B., Broadway, P.R., Sanchez, N.C., Hutcheson, J.P., Ellis, G.B., Holland, B.P., Ballou, M.A., Carroll, J.A. 2020. Acute immunological and metabolic responses of beef heifers administered transdermal flunixin meglumine at various times relative to a respiratory disease challenge. American Journal of Veterinary Research. 81(3):243-253. https://doi.org/10.2460/ajvr.81.3.243.
DOI: https://doi.org/10.2460/ajvr.81.3.243

Interpretive Summary: Scientists from the Livestock Issues Research Unit, Texas Tech University, Merck Animal Health and Cactus Feeders conducted a collaborative study to determine if altering the time of transdermal flunixin meglumine (TFM) administration relative to a viral-bacterial bovine respiratory disease (BRD) challenge in beef cattle would reduce the severity of the BRD symptoms. While TFM is approved for reduction of fever and clinical symptoms of inflammation associated with BRD, there is little data regarding the effects of TFM on inflammatory and immunological markers. Therefore, this study was conducted to quantify the effects of TFM on the inflammatory and immune responses of beef heifers to a BRD challenge, and to test the effects of administering TFM at different times before, during, and after the BRD challenge. Results from this study indicate that TFM is effective for fever reduction when applied during, but not prior to, a BRD challenge without affecting the immune or metabolic variables measured. Transient reduction of the activity of neutrophils through L-selectin expression and phagocytic and oxidative burst activity in the presence of TFM could indicate a reduction in BRD associated inflammation. Therefore, application of TFM during a BRD event appears to be a viable strategy to reduce fever without negative effects to the immune response of beef cattle during the disease recovery period. These data will be of interest to researchers working in the fields of cattle health and well-being, and bovine immunology, and to bovine veterinary practitioners, feedlot managers and beef cattle producers.

Technical Abstract: The objective of this study was to determine effects of altering the time of transdermal flunixin meglumine (TFM) administration relative to a viral-bacterial respiratory challenge in beef cattle. Thirty-two beef heifers (170 ± 21.1 kg BW) were assigned to one of four treatments: 1) Control (CON), receiving no TFM, 2) Arrival (ARR), receiving TFM at -144 hour, 3) Viral (VIR), receiving TFM at -72 hour, or 4) Bacterial (BAC), receiving TFM at 0 hour. At -72 hour, heifers were challenged intra-nasally with 1×108 plaque-forming units of bovine herpesvirus-1. At 0 hour, heifers were challenged intra-tracheally with an average dose of 1.18×106 colony-forming units of Mannheimia haemolytica, fitted with an indwelling jugular catheter, and moved into individual bleeding stalls indoors for collection of serial blood samples. Vaginal temperature was greatest (P = 0.04) for CON compared to VIR and BAC, and similar between CON and ARR. Leukocyte concentrations, cytokines, haptoglobin, glucose, NEFA, cortisol, and urea N were similar among treatments (P = 0.16). Neutrophil oxidative burst capacity decreased (P < 0.01) in ARR and VIR at 0 hour compared to (BAC+CON)/2. Neutrophil L-selectin expression decreased in VIR at 0 hour (P < 0.01) compared to all other treatments at those times. These data indicate that transdermal flunixin meglumine is effective for pyrexia reduction when applied during, but not prior to, a respiratory disease challenge without affecting the immune or metabolic variables measured. Transient reduction of the activity of neutrophils through L-selectin expression and phagocytic and oxidative burst activity in the presence of TFM could indicate a reduction in BRD associated inflammation.