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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Livestock Issues Research » Research » Publications at this Location » Publication #304001

Title: Effects of zilpaterol hydrochloride on blood gas, electrolyte balance, and pH in feedlot cattle

item BURSON, WILLIAM - Texas Tech University
item THOMPSON, ALEX - Texas Tech University
item JENNINGS, MICHAEL - Texas Tech University
item Carroll, Jeffery - Jeff Carroll
item Sanchez, Nicole
item HERGENREDER, JERILYN - Texas Tech University
item BAGGERMAN, JESSICA - Texas Tech University
item RAGLAND, BRADY - Texas Tech University
item SHARON, KATE - Texas Tech University
item SCHMIDT, TANNTER - Texas Tech University
item MURRAY, EVAN - Texas Tech University
item RIBEIRO, FLAVIO - Texas Tech University
item JOHNSON, BRADLEY - Texas Tech University
item RATHMANN, RYAN - Texas Tech University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/12/2014
Publication Date: 7/25/2014
Citation: Burson, W.C., Thompson, A.J., Jennings, M.A., Carroll, J.A., Sanchez, N.C., Hergenreder, J.E., Baggerman, J.O., Ragland, B.J., Sharon, K.S., Schmidt, T.R., Murray, E.S., Ribeiro, F.R., Johnson, B.J., Rathmann, R.J. 2014. Effects of zilpaterol hydrochloride on blood gas, electrolyte balance, and pH in feedlot cattle. Journal of Animal Science Supplement. 92(E-Suppl. 2):77. (Abstract #151).

Interpretive Summary:

Technical Abstract: The objective of this study was to examine the effects of zilpaterol hydrochloride (ZH) on blood gas, electrolyte balance and pH in feedlot cattle. Black-hided steers and heifers (n=96) were sourced from a commercial feedlot and transported to the Texas Tech University Beef Center in New Deal, TX. Cattle were weighed and scanned using real-time ultrasound. Resulting data were used to predict empty body fat percentage (pEBF %). Steers (n=48; body weight = 520 ± 30.4 kilograms; pEBF % = 26.2 ± 1.9) and heifers (n=48; body weight = 466 ± 29.5 kilograms; pEBF % = 26.7 ± 1.7) were blocked within gender by pEBF % in a completely randomized block design and randomly assigned to pen (2 pens/block; 4 head/pen) and treatment (6 pens/treatment): 1) control heifers (HC), 2) ZH heifers (HZ), 3) control steers (SC), 4) ZH steers (SZ). Venous blood was collected in lithium heparinized tubes through the use of jugular venipuncture on day 5, 10, 15 and 20 of the ZH treatment period. Blood samples were placed on ice and transported to an on-site station for prompt analysis. Data were analyzed as repeated measures to assess effects due to treatment. ZH treatment significantly increased potassium (K) concentration (P < 0.0001). Calcium (Ca) concentration was reduced in both genders; but, a significant gender x treatment interaction (P = 0.0376) revealed that ZH decreased Ca with a greater magnitude in steers relative to heifers. ZH treated cattle expressed a tendency for a lower partial pressure of oxygen (pO2; P = 0.082) relative to control. No significant gender x treatment interactions or main effects were detected (P = 0.14) for blood pH, partial pressure of carbon dioxide (pCO2), oxygen saturation (SO2C), sodium (Na) concentration or percentage of hematocrit (Hct). Collectively, these data suggest that only minor differences exist between ZH and control cattle with respect to blood gases and pH, such that a causative effect cannot be assumed. The alterations in K and Ca indicate that biologically significant differences in the cation-anion difference (CAD) may exist when comparing treatment groups. Furthermore, the significant reduction in blood Ca concentration in ZH treated cattle provides more insight to the well-known reduction in post-mortem tenderness associated with cattle fed a ß-adrenergic agonist.