Alphaxalone/alphadolone anaesthesia in the lamb

Alphaxalone/alphadolone (12 mg/ml) was administered by both the intramuscular and intravenous routes in an investigation of its action in newborn lambs. Useful anaesthesia was produced with an intravenous injection of 6 mg/kg bodyweight and with a divided intramuscular injection of either 9 or 12 mg/kg, one half of the dose being injected into the quadriceps mass of each hind leg. In all cases the recovery period was quiet and of short duration. Transient depressions of heart and respiratory rates were observed during anaesthesia but these were judged to be clinically acceptable. A single intramuscular injection was less effective probably because of slow absorption from the single site. The results suggest that this drug is a suitable injectable anaesthetic agent for the newborn lamb.