Effects of zilpaterol hydrochloride on methane production, total body oxygen consumption, and blood metabolites in finishing beef steers

K. E. Hales, A. P. Foote, D. W. Brake, T. M. Brown-Brandl, V. M. Artegoitia, H. C. Freetly

Research output: Contribution to journalArticlepeer-review

Abstract

An indirect calorimetry experiment was conducted to determine the effects of feeding zilpaterol hydrochloride (ZH) for 20 d on total body oxygen consumption, respiratory quotient, methane production, and blood metabolites in finishing beef steers. Sixteen Angus steers (initial BW = 555 ± 12.7 kg) were individually fed at ad libitum intake and used in a completely randomized design. The model included the fixed effects of dietary treatment, day, and treatment × day. Dry matter intake did not differ between the treatments (P = 0.89), but was greater on d 0 than any other day (P < 0.01). Oxygen consumption was not different between treatments (P = 0.79), but was different across day (P < 0.01) on d 7, 14, 21, and 28. Respiratory quotient was less for cattle fed ZH than control (P < 0.01), and also different across day (P < 0.01), being greater on d 7, 21, and 28 than d 3 or 21. Methane production (L/kg of DMI) was greater for steers fed the control vs. the ZH diet (P < 0.01), and it also differed by day (P < 0.01), being greater on d 21 and 28 than d 0, 3, 7, and 14. Nonesterified fatty acids were not different across treatments (P = 0.82), and there was no effect of treatment on β-hydroxybutyrate concentration (P = 0.45). Whole blood glucose concentrations were not affected by feeding ZH in this experiment (P = 0.76); however, lactate concentrations were reduced by feeding ZH (P = 0.03). Additionally, there was no treatment effect on ɑ-amino-N, blood glutamate, or glutamine (P ≥ 0.16). Plasma NH3 was not affected by ZH (P = 0.07), but plasma urea nitrogen was reduced by ZH (P < 0.01). Urinary creatinine was increased by steers receiving ZH (P = 0.01), and urine 3-methylhistidine (3-MH) concentrations were normalized to creatinine, the 3-MH:creatinine ratio decreased from d 0 to d 3 in steers fed ZH, and remained less than control steers until d 28. These data provide insight into how β-agonists alter nutrient partitioning and improve the efficiency of tissue accretion, mainly through decreased muscle protein turnover and altering the catabolic fuel for peripheral tissues.

Original languageEnglish
Pages (from-to)3192-3197
Number of pages6
JournalJournal of animal science
Volume95
Issue number7
DOIs
StatePublished - 2017

Keywords

  • Blood metabolites
  • Oxygen consumption
  • Zilpaterol hydrochloride

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