This blinded prospective study investigated analgesic effects of intramuscular (IM) butorphanol, meloxicam or intratesticular (IT) lidocaine for castration of 7-14 days old piglets under isoflurane anaesthesia. 66 piglets were randomly injected with: meloxicam IM (0.4 mg/kg; group M), butorphanol IM (0.2 mg/kg; group B), or both (group BM) 20 minutes prior to castration, or lidocaine IT (4 mg/kg (group ML4) or 8 mg/kg (group ML8)) together with meloxicam IM (0.4 mg/kg) under anaesthesia with 1.8% end-tidal isoflurane. Heart rate, respiratory rate, mean arterial blood pressure and end-tidal carbon dioxide were recorded. Anaesthesia quality was scored and postoperative behaviour assessed. As butorphanol caused unacceptable side effects, its use was stopped. Group M showed worse anaesthesia quality than ML4 and ML8 (higher incidence of movements: 11/17, 3/18 and 4/17, respectively). There were no significant differences between groups regarding parameters measured during castration. Postoperative behaviour did not differ between groups. For castration of 7-14 days old piglets under isoflurane anaesthesia, IT lidocaine provides an additional side effect free analgesia. AbstractThis blinded prospective study investigated analgesic effects of intramuscular (IM) butorphanol, meloxicam or intratesticular (IT) lidocaine for castration of 7-14 days old piglets under isoflurane anaesthesia. 66 piglets were randomly injected with: meloxicam IM (0.4 mg/kg; group M), butorphanol IM (0.2 mg/kg; group B), or both (group BM) 20 minutes prior to castration, or lidocaine IT (4 mg/kg (group ML4) or 8 mg/kg (group ML8)) together with meloxicam IM (0.4 mg/kg) under anaesthesia with 1.8% end-tidal isoflurane. Heart rate, respiratory rate, mean arterial blood pressure and end-tidal carbon dioxide were recorded. Anaesthesia quality was scored and postoperative behaviour assessed. As butorphanol caused unacceptable side effects, its use was stopped. Group M showed worse anaesthesia quality than ML4 and ML8 (higher incidence of movements: 11/17, 3/18 and 4/17, respectively). There were no significant differences between groups regarding parameters measured during castration. Postoperative behaviour did not differ between groups. For castration of 7-14 days old piglets under isoflurane anaesthesia, IT lidocaine provides an additional side effect free analgesia.

In this study dose rate combinations of ketamine, aza perone and romifidine were tested in 34 (G34) and 56 weeks (G56) old piglets according to a dose rate decision tree (DRT) to provide calm anaesthesia induc tion, reactionfree anaesthesia for castration and smooth recovery within 2 hours. When a combination failed to meet those criteria in 2 piglets, the next dosage of the DRT was tested. In G34 four combinations were tested in 14 piglets with dose rates of 1020 mg/kg ketamine, 3 mg/kg azaperone and 0.150.20 mg/kg romifidine IM. Induction was smooth in all piglets, but depth of anaes thesia or recovery (11 and 6 piglets) were insufficient. In G56 five combinations were tested in 37 piglets with dose rates of 1020 mg/kg ketamine, 34 mg/kg azape rone and 0.150.20 mg/kg romifidine IM. Induction was smooth in all piglets but 2. Depth of anaesthesia or re covery (17 and 7 piglets, respectively) were insufficient. In the present study with 34 and 56 weeks old piglets, acceptable quality of anaesthesia could not be achieved despite using high drug dose rates.