Infrared thermography or rectal temperature as qualification for targeted metaphylaxis in newly received beef steers and the effects on growth performance, complete blood count, and serum haptoglobin during a 42-day feedlot receiving period

• Published in: Applied Animal Science 2023-08, Vol.39 (4), p.213-226
• Main Authors: Smock, Taylor M., Broadway, P. Rand, Burdick Sanchez, Nicole C., Carroll, Jeffery A., Hoffman, Ashley A., Long, Nathan S., Manahan, Jeff L., McDaniel, Zach S., Theurer, Miles E., Wells, Jim E., Hales, Kristin E.
• Format: Article
• Language: English
• Subjects: bovine respiratory disease; feedlot cattle; metaphylaxis; receiving period
• ISSN: 2590-2865; 2590-2865
• DOI: 10.15232/aas.2022-02370

The objective was to evaluate rectal tem- perature and infrared thermography as qualification for targeted metaphylaxis, and effects on clinical health, growth performance, complete blood count, and serum haptoglobin in newly received beef steers during a 42-d feedlot receiving period. Crossbred beef steers (n = 240; arrival BW = 258 ± 22.5 kg) were used. Experimental treatments were arranged as a generalized complete block design: sterile saline (NCON); conventional metaphylaxis administered to all steers (CONV); targeted metaphylaxis administered to steers with rectal temperature ≥39.7°C (RECT); or targeted metaphylaxis administered to steers with ocular infrared temperature ≥39.7°C (EYE). Body weight and blood samples for quantification of complete blood count and serum haptoglobin were collected on d 0, 14, and 42 relative to metaphylaxis. Metaphylaxis was adminis- tered to 0% of NCON, 100% of CONV, 48.9% of RECT, and 48.6% of EYE steers (P < 0.01). Therapeutic bovine respiratory disease (BRD) treatment rate did not differ (P = 0.16), although overall BRD treatment rate was minimal. Metaphylaxis was 62.5% of total active antimicrobial compound administered to RECT and 32.1% of total ac- tive antimicrobial compound administered to EYE. Both methods of targeted metaphylaxis decreased percentage of animals administered antimicrobials relative to CONV (P < 0.01), but total milligrams of active drug compound administered was not different (P = 0.65). Body weight, DMI, DMI as 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 d 0 to 14, where CONV was greatest, RECT and EYE were intermediate, and NCON was least. Day 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 hematologic treatment differences were observed (P ≥ 0.22). Overall BRD morbidity was unexpectedly low in the present study. Both methods of targeted metaphylaxis decreased the propor- tion of animals administered antimicrobials relative to conventional metaphylaxis; however, total milligrams of active drug compound administered was not different. The ADG of steers administered targeted metaphylaxis based on rectal temperature did not differ from those ad- ministered conventional metaphylaxis. Use of targeted metaphylaxis with measures of body temperature may decrease the proportion of