Most herding breeds, including Australian Shepherds, seem to be sensitive to anesthetic drugs even if the are MDR1 negative. Typically, I avoid non-reversible medications for premedication like acepromazine and ketamine, and reduce the doses of all drugs for anesthesia.
Cerenia 1 mg/kg SC, IV
Hydromorphone 0.1 mg/kg IM, or
0.05 mg/kg IV
Propofol 4-6 mgkg IV
Considerations: You can add midazolam at 0.2 mg/kg IV OR dexmedetomidine at 1-2 mcg/kg IV if the patient is very nervous. However, I tend to use a "less is more" approach with these patients and see how they respond to the initial premedication. If you need to reverse the hydromorphone you may use naloxone at 0.02-0.04 mg/kg IM. The midazolam can be reversed with 0.02 mg/kg flumazenil IV and the dexmedetomidine can be reversed with an equal volume of atipamezole IM.
Sciatic/saphenous block: ropivicaine 0.3 mls/kg total
Lumbosacral epidural: bupivicaine or ropivicaine 0.3 mg/kg
Local infiltration of the surgical site: bupivicaine or ropivicaine 2 mg/kg
Fluid therapy: 3 mls/kg/hr with a balanced crystalloid
NSAIDS – either carprofen 2.2 mg/kg SC or meloxicam 0.1 mg/kg SC initially
Gabapentin 10 mg/kg PO q8 hrs