Location: Livestock Issues ResearchTitle: Evaluation of the effects of zilpateral hydrochloride supplementation on catecholamin response and other blood metabolites following a combined corticotropin releasing hormone and vasopressin challenge Author
|Buntyn, Joe - University Of Nebraska|
|Schmidt, Ty - University Of Nebraska|
|Sieren, Sara - University Of Nebraska|
|Erickson, Galen - University Of Nebraska|
|Jones, Steven - University Of Nebraska|
|Carroll, Jeffery - Jeff Carroll|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/3/2015
Publication Date: 3/1/2015
Citation: Buntyn, J.O., Sanchez, N.C., Schmidt, T.B., Sieren, S.E., Erickson, G.E., Jones, S.J., Carroll, J.A. 2015. Evaluation of the effects of zilpateral hydrochloride supplementation on catecholamin response and other blood metabolites following a combined corticotropin releasing hormone and vasopressin challenge. Journal of Animal Science Supplement. J.Anim.Sci. 93(E-Supplement 2):38 (Abstract#83).
Technical Abstract: The stress response of cattle supplemented with zilpaterol hydrochloride (ZH) has become a topic due to anecdotal claims of supplemented cattle responding poorly to stress. This study was designed to determine if differences exist in the catecholamine and blood metabolite response of ZH-supplemented cattle when exposed to a metabolic stress challenge. Heifers (n=18; 596±39 kilograms of body weight) were randomized into two treatment groups: 1) Control (CON): finishing diet with no ZH, and 2) Zilpaterol (ZIL): finishing diet with ZH (7.56 grams/ton dry matter basis). Zilpaterol heifers were supplemented ZH for 20 days, with a 3 day withdraw period. On day 20 of supplementation, all heifers were fitted with indwelling jugular catheters. On day 24, starting at 0800 hours (2 hours prior) and continuing until 1600 hours (8 hours post), blood samples were collected at 60-minute intervals for serum and plasma. At 1000 hours (day 24), heifers received an i.v. bolus of corticotropin releasing hormone (CRH; 0.3 micrograms per kilogram body weight) and vasopressin (VP; 1.0 micrograms per kilogram body weight) to activate the stress axis. Serum was separated and stored at -80 degrees Celcius until analyzed for creatine phosphokinase (CPK), creatine, Ca, P, Na, K, and liver enzymes. Plasma samples were collected in EDTA vacutainers, separated, flash frozen, and stored at -80 degrees Celcius until analyzed for catecholamines. Data were analyzed with the MIXED procedure for repeated measures (SAS). There was only a treatment effect (P<0.02) for Ca and K; ZIL had decreased concentrations during the CRH/VP challenge. There was also only a treatment effect for CPK (P=0.05) and creatine (P=0.003); ZIL had increased concentrations during CRH/VP challenge. A treatment x time effect (P=0.02) was observed for P. Concentrations of P were similar from -2 hours prior to 6 hours post challenge. At 7 hours post challenge, CON heifers had less P compared to ZIL heifers. There were no differences observed (P=0.22) for liver enzymes aspartate transaminase and gamma glutamyltransferase. There was only a treatment effect (P<0.05) for alkaline phosphatase and sorbitol dehydrogenase; CON heifers had greater concentrations, when compared to ZIL. There was only a treatment effect (P=0.04) for epinephrine concentrations; CON heifers having greater concentrations, when compared to ZIL. There were no difference (P=0.94) for norepinephrine concentrations. While some variations were observed between ZIL and CON heifers in terms of response to the CRH/VP challenge, these alterations appear to be minor. Based upon these results, in this experimental setting, supplementation of ZH did not drastically alter the ability of cattle to effectively respond to stressful stimuli.