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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Livestock Issues Research » Research » Publications at this Location » Publication #403457

Research Project: Environmental and Management Influences on Animal Productivity and Well-Being Phenotypes

Location: Livestock Issues Research

Title: The use of random metaphylaxis administered 0, 33, 66, or 100% at feedlot arrival on health outcomes, complete blood count, and growth performance of high-risk beef cattle

item HANRATTY, ASHLEE - Texas Tech University
item Broadway, Paul
item Sanchez, Nicole
item Carroll, Jeffery - Jeff Carroll
item HOFFMAN, ASHLEY - Texas Tech University
item MANAHAN, JEFF - Texas Tech University
item MCDANIEL, ZACH - Texas Tech University
item LINE, DALTON - Texas Tech University
item DORNBACH, COLTEN - Texas Tech University
item SMOCK, TAYLOR - Texas Tech University
item THEURER, MILES - Veterinary Research And Consulting Services Llc
item GALYEAN, MICHAEL - Texas Tech University
item HALES, KRISTIN - Texas Tech University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2023
Publication Date: 11/1/2023
Citation: Hanratty, A.N., Broadway, P.R., Sanchez, N.C., Carroll, J.A., Hoffman, A.A., Manahan, J.L., McDaniel, Z.S., Line, D.J., Dornbach, C.W., Smock, T.M., Theurer, M.E., Galyean, M.L., Hales, K.E. 2023. The use of random metaphylaxis administered 0, 33, 66, or 100% at feedlot arrival on health outcomes, complete blood count, and growth performance of high-risk beef cattle. Journal of Animal Science Supplement.

Interpretive Summary:

Technical Abstract: Our objective was to evaluate the effects of random metaphylaxis administered at 0, 33, 66, and 100% on clinical health, growth performance, and complete blood cell count in high-risk beef cattle during a 35-day receiving period. Crossbred beef steers (n = 216; arrival BW = 197 ± 6.4 kg) were used in a generalized complete block design consisting of 2 source blocks and 4 treatments. Experimental treatments and steers were randomly assigned to pen within source block: 1) negative control, subcutaneous injection with sterile saline (NCON); 2) 33% of steers/pen given metaphylaxis (33M); 3) 66% of steers/pen given metaphylaxis (66M); and 4) positive control; conventional metaphylaxis given to 100% of steers (CONV). Body weight and blood samples for quantification of complete blood count were collected on days 0, 14 and 35. Pen was considered the experimental unit for all analyses. Continuous data were analyzed using PROC MIXED and categorical data were analyzed as a binomial proportion using PROC GLIMMIX. Treatment was included in the model as a fixed effect and source block was included as a random effect. Complete blood counts were analyzed as repeated measures, where day was the repeated statement and pen within treatment was the subject. The percentage of steers treated for bovine respiratory disease once and twice was greater in NCON and 33M than 66M or CONC (P < 0.01). Neither BW on day 35, nor average daily gain from d 0 to 35 differed among treatments (P > 0.65). Nevertheless, dry matter intake (DMI) and DMI as a percentage of BW from day 0 to 35 was greater for 66M and CONV than NCON or 33M (P < 0.03). While complete blood counts changed over time (P < 0.01), no variables measured were affected by treatment. Arrival metaphylaxis can be administer to 66% of cattle at random without increasing the percentage given antibiotic therapy at least once while simultaneously increasing DMI.