title: Effect of butorphanol on thermal nociceptive threshold in healthy pony foals.
abstract: BACKGROUND
  Pain management is an important component of foal nursing care, and no objective data currently exist regarding the analgesic efficacy of opioids in foals.
  
  
  OBJECTIVE
  To evaluate the somatic antinociceptive effects of 2 commonly used doses of intravenous (i.v.) butorphanol in healthy foals. Our hypothesis was that thermal nociceptive threshold would increase following i.v. butorphanol in a dose-dependent manner in both neonatal and older pony foals.
  
  
  METHODS
  Seven healthy neonatal pony foals (age 1-2 weeks), and 11 healthy older pony foals (age 4-8 weeks). Five foals were used during both age periods. Treatments, which included saline (0.5 ml), butorphanol (0.05 mg/kg bwt) and butorphanol (0.1 mg/kg bwt), were administered i.v. in a randomised crossover design with at least 2 days between treatments. Response variables included thermal nociceptive threshold, skin temperature and behaviour score. Data within each age period were analysed using a 2-way repeated measures ANOVA, followed by a Holm-Sidak multiple comparison procedure if warranted.
  
  
  RESULTS
  There was a significant (P<0.05) increase in thermal threshold, relative to Time 0, following butorphanol (0.1 mg/kg bwt) administration in both age groups. No significant time or treatment effects were apparent for skin temperature. Significant time, but not treatment, effects were evident for behaviour score in both age groups.
  
  
  CONCLUSIONS
  Butorphanol (0.1 mg/kg bwt, but not 0.05 mg/kg bwt) significantly increased thermal nociceptive threshold in neonatal and older foals without apparent adverse behavioural effects.
  
  
  CONCLUSIONS
  Butorphanol shows analgesic potential in foals for management of somatic painful conditions.
authors.affiliation: Department of Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Florida, USA.
authors.forename: K T
authors.initials: KT
authors.lastname: McGowan
authors.forename: J R
authors.initials: JR
authors.lastname: Elfenbein
authors.forename: S A
authors.initials: SA
authors.lastname: Robertson
authors.forename: L C
authors.initials: LC
authors.lastname: Sanchez
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002077:Butorphanol / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D006734:Horse Diseases / Q000209:etiology / Q000517:prevention & control*; D006736:Horses; D006358:Hot Temperature / Q000009:adverse effects; D010146:Pain / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary*; D010147:Pain Measurement / Q000379:methods / Q000662:veterinary
chemical_list: D000701:Analgesics, Opioid; D002077:Butorphanol