Infrared thermography or rectal temperature as qualification for targeted metaphylaxis in high-risk, newly received beef steers and the effects on growth performance, complete blood count, and serum haptoglovin during...

Authors: SMOCK, TAYLOR - Texas Tech University; Broadway, Paul; Sanchez, Nicole; Carroll, Jeffery - Jeff Carroll; HOFFMAN, ASHLEY - Texas Tech University; LONG, NATHAN - Texas Tech University; MANAHAN, JEFF - Texas Tech University; MCDANIEL, ZACH - Texas Tech University; THEURER, MILES - Veterinary Research And Consulting Services Llc; Wells, James - Jim; HALES, KRISTIN - Texas Tech University

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2023
Publication Date: 8/15/2023
Citation: Smock, T.M., Broadway, P.R., Sanchez, N.C., Carroll, J.A., Hoffman, A.A., Long, N.S., Manahan, J.L., McDaniel, Z.S., Theurer, M.E., Wells, J., Hales, K.E. 2023. Infrared thermography or rectal temperature as qualification for targeted metaphylaxis in high-risk, newly received beef steers and the effects on growth performance, complete blood count, and serum haptoglovin during a 42-day feedlot receiving period. Applied Animal Science. 39(4):213-226. https://doi.org/10.15232/aas.2022-02370.
DOI: https://doi.org/10.15232/aas.2022-02370

Interpretive Summary: Body temperature (BT) is often used to evaluate the health status of cattle and assist in the diagnosis and treatment of disease. The most common method for measuring BT in cattle production is rectal temperature (RT), as it is relatively simple and inexpensive compared to alternative methods. However, measuring RT can produce inaccurate results that are difficult to interpret, as it is time consuming and invasive, thus creating additional stress on the animal. Amid efforts to decrease antimicrobial use in feedlots, metaphylaxis (i.e., treatment of a group of animals without evidence of disease) remains an important disease management tool. Therefore, scientists from Texas Tech University and ARS' Livestock Issues Research Unit collaborated on a study to evaluate rectal temperature and infrared thermography of the eye as methods of qualification for targeted metaphylaxis. Parameters measured included subsequent impacts on clinical health, growth performance, biological markers of stress and health in high-risk beef steers during the feedlot receiving period. Results suggest that use of targeted preventatives with measures of body temperature may decrease total antimicrobial use while maintaining optimal health and growth performance outcomes. This data will be of interest to beef feedlot producers, veterinarians, and beef cattle scientists.

Technical Abstract: The objective of this study was to evaluate rectal temperature and infrared thermography as qualification for targeted metaphylaxis and subsequent effects on clinical health, growth performance, complete blood count, and serum haptoglobin in high-risk, newly received beef steers during the feedlot receiving period. Crossbred beef steers (n = 240; arrival BW = 258 ± 22.5 kg) were used where pen was the experimental unit. Experimental treatments were arranged as a generalized complete block design: injection with sterile saline (NCON); conventional metaphylaxis administered to all steers (CONV); targeted metaphylaxis administered to steers with rectal temperature > 39.7 degree C (RECT); or targeted metaphylaxis administered to steers with ocular infrared temperature > 39.7 degree C (EYE). Body weight and blood samples for quantification of complete blood cell count and serum haptoglobin were collected on days 0, 14, and 42 relative to metaphylaxis. Metaphylaxis was administered to 0% of NCON, 100% of CONV, 48.9% of RECT, and 48.6% of EYE steers (P < 0.01). Therapeutic BRD treatment rate did not differ (P = 0.16), and the overall BRD treatment rate was minimal. Metaphylaxis accounted for 83.3% of total antimicrobials administered to RECT and 58.7% of total antimicrobials administered to EYE. Both methods of targeted metaphylaxis decreased total mL of antimicrobials administered relative to CONV metaphylaxis (P < 0.01). Body weight, DMI, DMI as a percentage of BW, and G:F did not differ at any time point (P > 0.07). A tendency (P = 0.06) was observed for ADG from day 0 to 14, where CONV was greatest, RECT and EYE were intermediate, and NCON was least. Likewise, from days 0 to 42, ADG was greatest in CONV and RECT, least in NCON, and intermediate in EYE (P < 0.01). Platelet count tended (P = 0.10) to be greatest in NCON and RECT, followed by EYE and CONV. No further treatment differences in complete blood count or serum haptoglobin concentration were observed (P > 0.22). Both methods of targeted metaphylaxis decreased antimicrobial administration relative to conventional metaphylaxis. The ADG of steers administered targeted metaphylaxis based on rectal temperature did not differ from those administered conventional metaphylaxis. Metaphylaxis is a widely used disease management tool in feedlots and use of targeted preventatives with measures of body temperature may decrease total antimicrobial use while maintaining optimal health and growth performance outcomes.