Farm animal anaesthesia and surgery

Question 1

How long to fast different animals before anaesthesia

Answer 1

> Small ruminants (including calves): 12-18 hours
Adult cattle: 24-36 hours
Suckling animals: 1-2 hours
Pigs: 12 hours

Question 2

What body changes does starvation in ruminants cause

Answer 2

Hypoglycaemia, metabolic acidosis/compensatory alkalosis
Hypokalaemia

Question 3

Withdrawel times of xylazine

Answer 3

48hrs in milk
72 hrs in meat

Question 4

Drugs authorised in cattle

Answer 4

Ketamine, detomidine, xylazine, some NSAIDs, procaine

Question 5

What side effect can alpha 2 agonists give

Answer 5

Hypoxaemia even in health animals

Question 6

Which small ruminant is especially sensitive to xylazine and its respiratory effects

Answer 6

Goats

Question 7

Which species is xyzaline not very effective in

Answer 7

Pigs
but still get side effects

Question 8

What consideration should we take when injecting ketamine near the spinal cord

Answer 8

Should be preservative free since these are neurotoxins

Question 9

How do pig airways differ from cattle

Answer 9

Narrower

Question 10

How can we do endotracheal intubation in cattle

Answer 10

Direct palpation of the epiglottis and arytenoids with finger; lower epigottis and then insert tube with other hand

Question 11

Why should we make sure nose is above the heart with anaesthetic positioning/recovery

Answer 11

They are obligate nasal breathers
Want to avoid oedema which constricts nasal passages

Question 12

What risk does hypersalivation under GA pose for ruminants

Answer 12

Dehydration
Metabolic acidosis

Question 13

What can we do to prevent bloating during anaesthetic and what do we need to be aware of

Answer 13

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

Question 14

What does fast breathing in animals starved for sugery indicate

Answer 14

Trying to compensale for metabolic acidosis

Question 15

What is malignant hyperthermia

Answer 15

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

Question 16

How to do locoregional anaesthesia for dehorning a goat

Answer 16

Block cornual branches of the infratrochlear nerve (lateral canthus of eye) and lacrimal nerve (medial canthus of eye)

Question 17

How is dehorning locoregional anaesthesia different in cattle to sheep

Answer 17

Do a blind ring block around branches of cornual nerve

Question 18

Difference between what is blocked during line block and inverted L block

Answer 18

In line block, just desensitises muscle (for incision)

Inverted L block involved paravertebral block too which desensitises the viscera as well

Question 19

How do paravertebral blocks work

Answer 19

Block nerves innervating the flank and abdominal wall and their spinal emergence

Question 20

What might a transversus abdominis plane block be used for and what does it desensitise

Answer 20

For repairing umbilical hernia in a calf
- Desensitises ventrolateral abdominal wall and gives somatic pain block (not visceral

Question 21

What drugs are suitable for IV locoregional anaesthetic

Answer 21

Lidocaine without adrenaline (would be off license)

NB: can’t use procaine

Question 22

How long to keep tourniquet on for during locoregional anaesthesia

Answer 22

30 mins

Question 23

What drugs can we use for neuraxial anaesthesia and which one do we need to be careful with

Answer 23

Local anaesthetics BUT must be aware of motor block
Opioids
Alpha 2 agonists e.g medetomidine, xylazine
Ketamine

Question 24

Where do we do epidural anaesthesia in goats

Answer 24

Lumbosacral or sarcococcygeal

Question 25

Where do we do epidural anaesthesia in cattle

Answer 25

Usually sacrococcygeal or coccygeal (rarely use lumbosarcal space; need to be more aware of motor block

Question 26

Intrathecal vs epidural technique

Answer 26

Epidural - above dura mater in epidural space; should NOT see csf in needle hub Intrathecal; in subarachnoid space i.e below arachmoid membrane; will see csf in needle hum

Question 27

Type of block gives with intrathecal instead of epidural

Answer 27

Get quicker more intense block but doesnt last as log

Question 28

What does CSF at top of needle during epidural anaesthesia suggest

Answer 28

Have done too far; are now intrathecal

Question 29

Which farm species is vomiting at recovery especially likely

Answer 29

Pigs

Question 30

What considerations do we have before farm animals surgery

Answer 30

Always do prophylactic antibiotics because procedures will be dirty or contaminated Ensure animal covered for clostridia vaccine; if not need to have penicillin

Question 31

Why is vasectomy more commonly done in sheep than cattle

Answer 31

Because teasers are used for oestrus stimulation, ovulation synchronisation and advancing breeding season rather than jsut for heat detection as in cattlw

Question 32

How are sheep vs cows positioned for vasectomy

Answer 32

Cow = standing or lateral recumbency Sheep = dorsal recumbency/propped up sitting

Question 33

What things could be done during a vasectomy to reduce the risk of recannalisation of the vas deferens

Answer 33

Cauterise the ends Suture the proximal end to the outside of the scrotum

Question 34

What can we do after a vasectomy to check we have taken out the right bit

Answer 34

Squeeze vas deferents onto slide and look for semen Store in formalin for histology later if efficacy questioned

Question 35

How long should we wait after vasectomy before using the teaser

Answer 35

6 weeks or 6 ejacultes

Question 36

What does an epididyectomy involve

Answer 36

Bluntly dissect the tail of epididymis away from the testicle and ligate

Question 37

How long to wait before using epididyectomised animal as a teaser

Answer 37

6 weeks

Question 38

What is a tracheotomy used for

Answer 38

Emergency temporary measure for animals in respiratory distress

Question 39

What is the difference betweeen a tracheotomy and tracheostomy

Answer 39

Tracheostomy = a permanent measure used to get animals to slaughter

Question 40

What is a tibial neurectomy used for

Answer 40

Treatment of spastic paresis in cattle

Question 41

How is tibial neurectomy performed (position, anaesthesia)

Answer 41

Lateral recumbency Done with sedation and cranial epidural or under GA

Question 42

How to tell you have the right nerve to cut in tibial neurectomy

Answer 42

Stimulate two nerves near head of biceps femoris - Tibial nerve causes digital flexion and hock extension

Question 43

Post op care for tibial neurectomy

Answer 43

Limit exercise for 2 weeks then remove skin sutures Warn farmer of risk of getting a problem in the other lim

Question 44

How is a gastrocnemium tenectomy done and when might we use it

Answer 44

Cut gastrocnemius tendom transversely and remove 2cm portion Cut superficial flexor tendon through half diameter Used to get cattle with spastic paresis to slaughter

Question 45

How soon do we need to deal with teat lacerations

Answer 45

Immediately as it is an emergency Should be cleaned, sutured and bandaged within 6 hour s

Question 46

What suture pattern is useful in teat surgery to relieve tension

Answer 46

Vertical mattress

Question 47

What is an issue that can be caused with using teat knives to remove obstructions

Answer 47

Will compromise the sphincter

Question 48

After what age do we need anaesthetic for supernumerary teat removal

Answer 48

3 months

Question 49

How is a tail amputation done

Answer 49

Caudal epidural Make V shaped incision on dorsal and ventral aspect of tail cranial to lesion Disarcticulate coccygeal vertebrae Suture up

Question 50

What surgical treatment is done in small ruminants with urolithiasis

Answer 50

Vermiform appendage amputation since this is the narrowest part of urinary tubular system so common site of blockage

Question 51

WHen might we perform a tube cystotomy

Answer 51

To restablish urine flow while allowing obstruction or rupture to resolve _ Done in valuable animals esp breeding ones where we need to maintain penile function

Question 52

What post op care do we need with tube cystotomy or urethrostomy

Answer 52

Therapy to acidify the urine

Question 53

What is a urethrostomy

Answer 53

Salvage procedure to deal with urolithiasis via diverting urine to a different place; perineal area

Question 54

ANALGESIA/anaesthesia for tube cystotomy

Answer 54

Dorsal recumbency Ideally GA could do sedation and LA