Farm animal anaesthesia and surgery Flashcards

1
Q

How long to fast different animals before anaesthesia

A

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

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2
Q

What body changes does starvation in ruminants cause

A

Hypoglycaemia, metabolic acidosis/compensatory alkalosis
Hypokalaemia

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3
Q

Withdrawel times of xylazine

A

48hrs in milk
72 hrs in meat

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4
Q

Drugs authorised in cattle

A

Ketamine, detomidine, xylazine, some NSAIDs, procaine

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5
Q

What side effect can alpha 2 agonists give

A

Hypoxaemia even in health animals

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6
Q

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

A

Goats

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7
Q

Which species is xyzaline not very effective in

A

Pigs
but still get side effects

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8
Q

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

A

Should be preservative free since these are neurotoxins

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9
Q

How do pig airways differ from cattle

A

Narrower

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10
Q

How can we do endotracheal intubation in cattle

A

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

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11
Q

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

A

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

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12
Q

What risk does hypersalivation under GA pose for ruminants

A

Dehydration
Metabolic acidosis

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13
Q

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

A

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

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14
Q

What does fast breathing in animals starved for sugery indicate

A

Trying to compensale for metabolic acidosis

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15
Q

What is malignant hyperthermia

A

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

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16
Q

How to do locoregional anaesthesia for dehorning a goat

A

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

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17
Q

How is dehorning locoregional anaesthesia different in cattle to sheep

A

Do a blind ring block around branches of cornual nerve

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18
Q

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

A

In line block, just desensitises muscle (for incision)

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

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19
Q

How do paravertebral blocks work

A

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

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20
Q

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

A

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

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21
Q

What drugs are suitable for IV locoregional anaesthetic

A

Lidocaine without adrenaline (would be off license)

NB: can’t use procaine

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22
Q

How long to keep tourniquet on for during locoregional anaesthesia

A

30 mins

23
Q

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

A

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

24
Q

Where do we do epidural anaesthesia in goats

A

Lumbosacral or sarcococcygeal

25
Q

Where do we do epidural anaesthesia in cattle

A

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

26
Q

Intrathecal vs epidural technique

A

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

27
Q

Type of block gives with intrathecal instead of epidural

A

Get quicker more intense block but doesnt last as log

28
Q

What does CSF at top of needle during epidural anaesthesia suggest

A

Have done too far; are now intrathecal

29
Q

Which farm species is vomiting at recovery especially likely

A

Pigs

30
Q

What considerations do we have before farm animals surgery

A

Always do prophylactic antibiotics because procedures will be dirty or contaminated

Ensure animal covered for clostridia vaccine; if not need to have penicillin

31
Q

Why is vasectomy more commonly done in sheep than cattle

A

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

32
Q

How are sheep vs cows positioned for vasectomy

A

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

33
Q

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

A

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

34
Q

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

A

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

35
Q

How long should we wait after vasectomy before using the teaser

A

6 weeks
or 6 ejacultes

36
Q

What does an epididyectomy involve

A

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

37
Q

How long to wait before using epididyectomised animal as a teaser

A

6 weeks

38
Q

What is a tracheotomy used for

A

Emergency temporary measure for animals in respiratory distress

39
Q

What is the difference betweeen a tracheotomy and tracheostomy

A

Tracheostomy = a permanent measure used to get animals to slaughter

40
Q

What is a tibial neurectomy used for

A

Treatment of spastic paresis in cattle

41
Q

How is tibial neurectomy performed (position, anaesthesia)

A

Lateral recumbency
Done with sedation and cranial epidural or under GA

42
Q

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

A

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

43
Q

Post op care for tibial neurectomy

A

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

44
Q

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

A

Cut gastrocnemius tendom transversely and remove 2cm portion
Cut superficial flexor tendon through half diameter

Used to get cattle with spastic paresis to slaughter

45
Q

How soon do we need to deal with teat lacerations

A

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

46
Q

What suture pattern is useful in teat surgery to relieve tension

A

Vertical mattress

47
Q

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

A

Will compromise the sphincter

48
Q

After what age do we need anaesthetic for supernumerary teat removal

A

3 months

49
Q

How is a tail amputation done

A

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

50
Q

What surgical treatment is done in small ruminants with urolithiasis

A

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

51
Q

WHen might we perform a tube cystotomy

A

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

52
Q

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

A

Therapy to acidify the urine

53
Q

What is a urethrostomy

A

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

54
Q

ANALGESIA/anaesthesia for tube cystotomy

A

Dorsal recumbency
Ideally GA
could do sedation and LA