Farm animal anaesthesia and analgesia

Question 1

What groups of medicines can be used in farm animals?

Answer 1

NSAIDs
LAs
Opioids
General anaesthesia agents
Sedatives

Question 2

Which LAs can be used in farm animals?

Answer 2

Procaine
Lidocaine listed in register

Question 3

Which opioids can be used in farm animals

Answer 3

Butorphanol listed in register but not licensed

Question 4

Which general anaesthesia agents can be used in farm animals?

Answer 4

Ketamine licensed
Some listed in register

Question 5

Which sedatives can be used in farm animals?

Answer 5

Xylazine and detomidine licensed

Question 6

You are called to a difficult calving on one of your dairy clients. The patient is a primiparous animal, and on examination you diagnose foetal-maternal disproportion (i.e. a big calf!). You’re fairly sure it will be possible to deliver the calf vaginally, but before beginning to apply traction you decide to develop an analgesic regime…
What methods of analgesia will you employ?

Answer 6

LA epidural - low dose - lidocaine or procaine
Add alpha 2 to epidural to prolong the effect of the epidural e.g., xylazine
Start new bottles when doing epidurals

NSAID to deal with post-delivery pain e.g., carprofen, meloxicam, ketoprofen
Give NSAIDs to neonate - pain in birth esp. if traction used - meloxicam has lowest side effects so best for calves

Question 7

Why are cattle poor candidates for GA?

Answer 7

Large rumen and small lungs

Question 8

You’re working in a busy mixed practice. A colleague asks you to anaesthetise a 12-week old dairy calf whilst they perform an umbilical hernia repair surgery. They expect the surgery to last 30-60 minutes, and the calf will need to be in dorsal recumbency for that time. Devise a plan for anaesthesia for this surgery.

Answer 8

IV NSAIDs for analgesia
Ketamine or xylazine/detomidine* - GA - 30 mins - top up if longer - add opioid (butorphanol) to lower dosage
LA around surgery site - procaine

*detomidine may be cheaper and longer lasting