Effects of intramuscular alfaxalone-midazolam combination in pigs

Abstract

The aim of this experimental study was to evaluate the sedative and cardiorespiratory effects of alfaxalone and midazolam after intramuscular administration in pigs. Fourteen pigs, weighing 18 to 22 kg, aged between 55 and 70 days, American Society of Anaesthesiologists classification 2, affected by congenital reducible umbilical hernia, were included in the study. Alfaxalone (5 mg/kg) and midazolam (0.5 mg/kg) mixed in the same syringe were administered into the neck muscle. Pain on injection, quality of sedation and time to achieve lateral recumbency were recorded. Heart rate (HR), respiratory frequency (fR), and rectal temperature (RT) were recorded at 0 (baseline: before drug administration), 10, 15, and 20 min after the injection. Oxygen saturation of haemoglobin (SpO2), arterial blood pH, arterial oxygen (PaO2) and carbon dioxide (PaCO2) tensions and bicarbonate concentration (HCO3-) were recorded at 10, 15, and 20 min after injection. Continuous data were analysed using a repeated-measure analysis of variance (ANOVA) and a P-value < 0.05 was considered significant. Ten animals out of fourteen showed no pain on injection, whereas the remaining four exhibited mild pain. The time from the end of injection to lateral recumbency was 266 ± 40 s. The quality of sedation ranged between good to very good. No significant changes in the variables monitored were observed between the time points. In conclusion, the intramuscular administration of alfaxalone and midazolam in pigs at the doses used induced reliable and fast sedation, without pain on injection and moderate respiratory effects.

Is the Piglet Grimace Scale (PGS) a Useful Welfare Indicator to Assess Pain after Cryptorchidectomy in Growing Pigs?

“…The pigs were pre-medicated with a combination of azaperone (2 mg/kg; Stresnil ® , Elanco Italia S.p.A., Sesto Fiorentino, Italy) and ketamine (10 mg/kg; Ketavet 100 ® , Intervet, Aprilia, LT, Italy), administered by intramuscular injection into the neck behind the base of the ear by using a 19 gauge needle connected to a line extension (75 cm, 1.3 mL volume, Sidam Medical Device ® , Italy). Pain on injection was scored using a simple descriptive scale modified [13]: score 0 = no pain (the animal is quiet and indifferent to the injection); score 1 = mild pain (movement of tail and turning of head towards injection site); score 2 = moderate pain (light grunts and attempts to remove needle); and score 3 = severe pain (strong vocalization and attempts to escape, requiring vigorous physical restraint). Time from end of injection to lateral recumbency was recorded.…”