Comparison of azaperone-detomidine-butorphanol-ketamine and azaperone-tiletamine-zolazepam for anaesthesia in piglets.

To investigate a combination of azaperone, detomidine, butorphanol and ketamine (DBK) in pigs and to compare it with the combination of azaperone, tiletamine and zolazepam (TZ). Prospective, randomized, blinded, cross-over study. Twelve clinically healthy crossbred pigs aged about 2 months and weighing 16-25 kg. Pigs were pre-medicated with azaperone (4 mg kg(-1)). Ten minutes later anaesthesia was induced with intramuscular DBK (detomidine 0.08 mg kg(-1), butorphanol 0.2 mg kg(-1), ketamine 10 mg kg(-1)) or TZ (tiletamine and zolazepam 5 mg kg(-1)). The pigs were positioned in dorsal recumbency. Heart and respiratory rates, posture, anaesthesia score, PaO(2), PaCO(2), pH and bicarbonate concentration were measured. t-test was used to compare the areas under time-anaesthesia index curve (AUC(anindex)) between treatments. Data concerning heart and respiratory rates, PaO(2), PaCO(2) and anaesthesia score were analysed with anova for repeated measurements. Wilcoxon signed rank test was used for the data concerning the duration of sedation and anaesthesia. The sedation, analgesia and anaesthesia lasted longer after DBK than TZ. The AUC(anscore) were 863 +/- 423 and 452 +/- 274 for DBK and TZ, respectively (p = 0.002). The duration of surgical anaesthesia lasted a median of 35 minutes (0-105 minutes) after DBK and a median of 15 minutes (0-35 minutes) after TZ (p = 0.05). Four pigs after DBK and six after TZ did not achieve the plane of surgical anaesthesia. The heart rate was lower after DBK than after TZ. Both treatments had similar effects on the other parameters measured. At the doses used DBK was more effective than TZ for anaesthesia in pigs under field conditions. The combinations can be used for sedation and minor field surgery in pigs. The doses and drugs chosen were insufficient to produce a reliable surgical plane of anaesthesia in these young pigs.