Sedation of Farm Animals

Question 1

Factors that influence which sedatives and local anaesthetic agents that can be administered to farm animals.

Answer 1

FOOD PRODUCING!
- Cascade.
- Withdrawal periods.
- Impact of injection reactions / infections.
PRODUCTION ANIMALS!
- Pregnancy.
- Welfare.
- Pain and stress impair production.
- Economic considerations.

Question 2

What sedatives have a UK Marketing Authorisation for farm animals?

Answer 2

Cattle – xylazine
–> IM (IV for some preparations but not all).
–> Care should be taken in the first month of pregnancy.
–> Contraindicated for use at the latter stages of pregnancy except parturition.
– Detomidine.
–> IM or IV.
–> Do not use in last trimester of pregnancy.
Pigs – Azaperone –> IM.

Question 3

Outline the major differences between the pharmacodynamics of alpha2-adrenoreceptor agonists in farm animal spp. and companion animals.

Answer 3

Situational awareness is vital w/ FA.
- Risk of recumbency.
- Paradoxical aggression dangerous esp. in heavy animals.
Rumenal tympany in ruminants due to reduced GI motility, and risk of regurgitation and subsequent aspiration.
High likelihood of pregnancy.
Dose important (xylazine dose 10 x less in cattle than in horses) (Pigs v resistant so dosage higher).
Atipamezole not routinely used (no MA).
Not given w/ opioids.
Pulmonary oedema in sheep following xylazine.

Question 4

What local anaesthetics have a UK MA?

Answer 4

Procaine hydrochloride plus epinephrine bitartrate (adrenaline).
- Trade names incl. Willcaine and Adrenacaine.
- Cattle.
- Not for IV, intra-articular or epidural injection.
- Care with extremities due to vasoconstriction.

Question 5

General principles for surgery in farm spp.

Answer 5

Consider if sedation required.
Use an appropriate local anaesthetic technique.
Consider administering NSAIDs.
Opioids NOT permitted for FAs.