Farm animal anaesthesia and surgery Flashcards
How long to fast different animals before anaesthesia
> Small ruminants (including calves): 12-18 hours
Adult cattle: 24-36 hours
Suckling animals: 1-2 hours
Pigs: 12 hours
What body changes does starvation in ruminants cause
Hypoglycaemia, metabolic acidosis/compensatory alkalosis
Hypokalaemia
Withdrawel times of xylazine
48hrs in milk
72 hrs in meat
Drugs authorised in cattle
Ketamine, detomidine, xylazine, some NSAIDs, procaine
What side effect can alpha 2 agonists give
Hypoxaemia even in health animals
Which small ruminant is especially sensitive to xylazine and its respiratory effects
Goats
Which species is xyzaline not very effective in
Pigs
but still get side effects
What consideration should we take when injecting ketamine near the spinal cord
Should be preservative free since these are neurotoxins
How do pig airways differ from cattle
Narrower
How can we do endotracheal intubation in cattle
Direct palpation of the epiglottis and arytenoids with finger; lower epigottis and then insert tube with other hand
Why should we make sure nose is above the heart with anaesthetic positioning/recovery
They are obligate nasal breathers
Want to avoid oedema which constricts nasal passages
What risk does hypersalivation under GA pose for ruminants
Dehydration
Metabolic acidosis
What can we do to prevent bloating during anaesthetic and what do we need to be aware of
Can use stomach tube to allow gas out
but this keeps cardia open so more risk of gastric fluid leaking up oesophagus and being inhaled
What does fast breathing in animals starved for sugery indicate
Trying to compensale for metabolic acidosis
What is malignant hyperthermia
An inherited condition of skeletal muscle in pigs; causes uncontrolled Ca2+ release from sarcoplasmic reticulum
–> Hypertermia, hypercapnia, ventricular arrhythimas, death
Can occur with inhalation anaesthetics
How to do locoregional anaesthesia for dehorning a goat
Block cornual branches of the infratrochlear nerve (lateral canthus of eye) and lacrimal nerve (medial canthus of eye)
How is dehorning locoregional anaesthesia different in cattle to sheep
Do a blind ring block around branches of cornual nerve
Difference between what is blocked during line block and inverted L block
In line block, just desensitises muscle (for incision)
Inverted L block involved paravertebral block too which desensitises the viscera as well
How do paravertebral blocks work
Block nerves innervating the flank and abdominal wall and their spinal emergence
What might a transversus abdominis plane block be used for and what does it desensitise
For repairing umbilical hernia in a calf
- Desensitises ventrolateral abdominal wall and gives somatic pain block (not visceral
What drugs are suitable for IV locoregional anaesthetic
Lidocaine without adrenaline (would be off license)
NB: can’t use procaine