Article Text

Pharmacokinetics of butorphanol in broiler chickens
  1. P. M. Singh, BVSc, MVSc,
  2. C. Johnson, BVSc, PhD, CertVA, DVA, DipECVA,
  3. B. Gartrell, BVSc, PhD, MACVSc,
  4. S. Mitchinson, BSc and
  5. P. Chambers, BVSc, PhD, DVA, MRCVS, MRCA
  1. Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand
  1. E-mail for correspondence p.m.singh{at}

Butorphanol tartrate (2 mg/kg) was injected intravenously in 18 healthy broiler chickens to study its pharmacokinetics. Plasma samples were analysed by a highly sensitive high-performance liquid chromatography with diode-array detection method and pharmacokinetic parameters were calculated from the mean pooled data. With non-compartmental analysis, the terminal half-life (T1/2.z) was 71.3 minutes, clearance was 67.6 ml/minute/kg and the apparent volume of distribution was 6.9 l/kg. The concentration-time curve was also fitted to a two-compartmental model. In this analysis, elimination half-life (T1/) was 69.3 minutes, clearance was 74.6 ml/minute/kg and volume of distribution at steady state was 5.6 l/kg. The micro rate constants k21, k12 and k10 were 0.034, 0.050 and 0.029, respectively. Butorphanol was well distributed in the chickens with rapid clearance. It remained above the minimum effective concentration for analgesia in mammals for approximately two hours in the chickens.

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  • Provenance not commissioned; externally peer reviewed

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