Production animal anesthesia

Question 1

Ruminants are not great candidates for deep sedation or general anesthesia, because they

Answer 1

might easily aspirate the rumen content during regurgitation.

If cattle are placed laterally or dorsally – the rumen gases can’t escape and tympany ensues which hinders normal breathing.

hypoventilation leads to hypoxia of course

Question 2

the main 2 side effects of sedated and anesthetized cattle

Answer 2

Hypoventilation and hypoxia are the main side effects of sedated and anesthetized cattle.

Question 3

a recumbent production animal patient is at risk of what due to position? (2)

Answer 3

pressure myopathy (can take max 20 min in one position)

nerve damage due to positional pressure (soft bedding should be used or foam pieces to cushion the animal)

Question 4

main risks associated with ruminant anesthesia (specifically xylazine) (3)

Answer 4

increased urine production (note poss. obstruction!)

increased salivation can lead to aspiration pneumonia

alfa2-agonists (xylazine) cause uterine contractions (last ⅓ of pregnancy) so abortion is a risk

Small ruminants more sensitive
* Especially goats!

Question 5

Describe preanesthetic fasting ruminants.

Answer 5

Let adult animals fast 12-24 hours (calves 12 hours).

But if we keep animal off feed for too long >24 hours, then the volume of the rumen decreases, but the content becomes liquidy – increased danger of aspiration.

Off water for 12-24 h before surgery, because a hungry animal tries to compensate hunger with drinking water.

Question 6

Small ruminants: fasting duration?
Neonatal ruminants fast?

Answer 6

Small ruminants: fasting 12-18h

Neonatal ruminants fast not over 2-4h (hypoglycemia)

Question 7

head and neck position for recumbent anesthetized ruminants?

Answer 7

Nose has to be lower than the head,
but the head has to be higher than the
neck (to avoid the aspiration)

Question 8

Anesthesia of <3 month old calves, IVFT

Answer 8

<3 month calves need 5% dextrose 3-5 ml/kg/h

with electrolyte solutions 3-7 ml/kg/h IV to avoid hypoglycemia

GLU should be measured intraoperatively (> 4,4 mmol/l)

Question 9

What IVFT products are necessary when there is great blood loss present or endotoxemic shock?

Answer 9

Hypertonic solutions 2-4 ml/kg IV during 10-20 min are necessary when there is great blood loss present or endotoxemic shock.

In order to pull fluid from the intracellular space into the vessels. Crystalloids should be administered later to correct the iatrogenic dehydration.
OR
Always give the animals either 20-30 l of water to drink
OR use a stomach tube to give 20-30 l of water

Question 10

There is high risk for what type of nerve dameg if adult cattle lay on the
hard ground over 20 min?

Answer 10

There is high risk for n. radialis paralysis in adult cattle if they lay on the hard ground over 20 min.

Soft bedding should be placed underneath the shoulder and front legs for longer procedures. Both front legs should be horizontally with the ground.

Question 11

α₂- agonist (xylazine) side effects in ruminants

Answer 11

Xylazine can cause bradycardia, hypotension, hypoxia, hypercapnia, pulmonary
oedema, hyperglycemia, hypoinsulinemia, increases the urine production up to
6x, oxytocin-like effect.

Xylazine alone does not give good visceral analgesia. It Inhibits swallowing, be wary of aspiration pneumonia.

Gastro-intestinal motility lowers ->
tympany, diarrhea follows in 12-24 h.

Question 12

xylazine dose for ruminants vs for horses

Answer 12

ruminants get 1/10 of the dose horses require of xylazine

are way more sensitive to it

Question 13

In ruminants: Xylazine induced Hyperglycemia may last up to

Answer 13

10 h (insulin in blood serum decreases)

Question 14

The main cause of death with xylazine is usually

Answer 14

Usually hypoxia with pulmonary oedema.

Question 15

α₂- agonist detomidine side effects in production animals

Answer 15

Bradycardia, hyperglycemia, increased urine production, higher heat stress chance, increases BP (xylazine decreases it), uterine contractions only with higher doses.

Question 16

detomidine vs xyalizine and blood pressure

Answer 16

Detomidine raises blood pressure,
xylazine lowers it.

Question 17

How much atipamezole to xylazine in production animals?

Answer 17

½ …1/3 of the dosage of xylazine

Not registered to production animals but still in use.

If ketamine is used then wait 30-40 min before administration.

Question 18

If atipamezole is used on an unsedated animal, it causes

Answer 18

hyperactivity, anxiety, kicking etc.

Question 19

2 alfa2-agonist reversal agents other than atipamezole?

Answer 19

yohimbine
tolazoline

Question 20

Ketamine effects in ruminants?

Answer 20

Strong analgetic effect.
Causes elevated HR and blood pressure, muscle stiffness, salivation.

In calves higher doses are used (up to 10mg/kg while adults get 2mg/kg)

Question 21

If a recently anesthetized animal is breathing with its mouth open this is a sign of?

Answer 21

hypoxia

Question 22

If a calf is taking a very long time to recover, it may be

Answer 22

hypoglycemic.

Question 23

Local anesthesia - If epinephrine is an additive in your lidocaine preparation, you might see

Answer 23

tissue or skin necrosis if the product is used as an infiltration block shallow or subcut.

Causes vasoconstriction and extends the effective time of the local.

Question 24

Local anesthesia risks - Large doses have a toxic effect on…?

Answer 24

on young animals especially.

Can cause nystagmus, low blood pressure, respiratory distress, collapse, death.

Small ruminants are especially sensitive to the toxic effect. Do not go over the 6 mg/kg dose!

With young animals and small ruminants use diluted solutions (0,5%-1,0%) instead.

Question 25

Proximal and distal paravertebral anesthesia

Answer 25

Are regional anesthesia.

Proximal (or dorsal) paravertebral anesth. is administered into a space immediately lateral to where the spinal nerves emerge from the intervertebral foramina.

Distal /or lateral) paravertebral anesth. is administered at the tips of the transverse processes of the vertebre.

Question 26

what does this picture show?

Answer 26

Distal paravertebral anesthesia

Question 27

what does this picture show?

Answer 27

L – anesthesia (or inverted 7 anesthesia)

Question 28

Answer 28

N.cornualis anesthesia, 2,5 cm below base of the horn, 1cm deep (nerve located under the
skin).

Adult cattle: local anesthetic 5 ml over the nerve + 5ml under the nerve + behind the horn.

Question 29

What does this picture show?

Answer 29

Caudal epidural anesthesia (high or low sacral).

Injection site between the sacrum and first tail vertebrae or the 1. and 2. tail vertebrae (diameter of the neural canal is 1,8-2 cm).

Removes sensation in the perineum, vulva, vagina and rectum. When injecting the local anesthetic should go in without any resistance.

Question 30

Anesthetics for enucleation in cattle.

Answer 30

Animal should be sedated and head should be fixated as well as possible.

Curved needle should be used for retrobulbar 4-point block anesthesia: 10-20ml 2% procaine/lidocaine.

Question 31

Teat anesthesia for cattle.

Answer 31

Animal should be in the chute, hind leg nearest operable teat fixated.

Infiltration anesthesia around the teat base with small needle. Anesthetic can be diluted.
Do not use local anesthetic with epinephrine or adrenaline.

Question 32

For the small ruminants, you can achieve analgesia and paralysis of the hind legs with…

Answer 32

Lumbosacral epidural anesthesia: Analgesia and paralysis of the hind legs (The back of the body to the diaphragm) in 5-15 mi, lasts for 1-2h.

Question 33

Most common Non-Steroidal Anti Inflammatory Drugs used in production animals (4)

Answer 33

flunixin meglumine
carprofen
ketoprofen
meloxicam (best choice for visceral pain)
(etc.)

Question 34

stresnil (trade name) is

Answer 34

active drug azaperone which is the most used sedative in pigs.

Dose 1-8 mg/kg (recommended up to 4 mg/kg).

Azaperone should be injected deep into the muscle layers, then leave animal in a calm place for 20 min.

Boars > 1 mg/kg can cause penis prolapse.

Pig body temperature can drop in a cool place!

Question 35

How long should you fast a pig for, before scheduled anesthesia?

Answer 35

24(6-10)h fasting before general anesthesia
(water should be available)

Salivation is a risk in pigs (aspiration pneumonia)

Question 36

Malignant hyperthermia of piglets

Answer 36

Skeletal muscles’ muscle fibres release Ca -> the muscles contract -> heat and lactate are thus produced.

Consequent, Metabolic acidosis, hyperkalemia.

Quick rise of the body temperature (>42 C°), stiff muscles, tachycardia, tachypnea.

• Hypoxia, cyanosis, hypotension
• Myoglobinuria with kidney failure

Pet pigs often very fat, cooling takes longer.

Question 37

treatment of Malignant hyperthermia in piglets

Answer 37

• Stop inhalation anesthesia, increase oxygen level
• Start manual ventilation
• Ice bags, cool IV solutions
• NaHC03 IV slow infusion, 1,5 mEq/kg (for the metabolic acidosis)
• Dantrolene (muscle relaxant) IV 2 mg/kg, then increase 10 mg/kg
• Ca, NaHCO3, glucose, insulin and artificial hyperventilation are important to
  adjust hyperkalemia.

Question 38

Biological relationship between glucose and potassium in the body.

Answer 38

Insulin promotes the uptake of glucose into cells but also facilitates the entry of potassium into cells along with glucose.

This insulin-mediated movement of potassium helps lower blood potassium.

(and vice versa, too much insulin can cause hypokalemia of the blood)

Question 39

Name 4 Premedications commonly used in pigs.

Answer 39

• Acepromazine 0,03-0,2 mg/kg IM/IV
• Azaperone 2.6mg/kg IM
• Diazepam 0,2-5mg/kg IM (0,2-0,5 mg/kg IV)
• Xylazine 1-2mg/kg IM

Question 40

Xylazine is not as effective in pigs as in…?

Answer 40

other animals.

Xylazine dose for pigs is considerably larger than the other production animals (pigs: dose 1-2 mg/kg IM or IV).

Xylazine is ineffective alone in pigs, but can be combined with ketamine, butorphanol or
midazolam.

Question 41

Tiletamine-zolazepam

Answer 41

Is a combo preparation.

Tiletamine is similar to ketamine.
Zolazepam is similar to diazepam (muscle relaxant).

• Dose 2-5 mg/kg IM, can be used alone or in combination with xylazine or butorphanol.

Question 42

Camelids are less sensitive to xylazine than

Answer 42

ruminants.

Question 43

Which need higher drug doses, Alpacas or llamas?

Answer 43

Alpacas need higher doses than llamas.

Question 44

How to Confirm death after euthanasia?

Answer 44

• Absence of pulse and corneal reflex
• Failure to respond to strong pinches to nose/interdigital space.
• No heart or respiratory sounds heard with stethoscope (listen for 3-5 minutes).
• Graying of mucous membranes
• Rigor mortis

Question 45

If an animal is stunned with a bolt
gun, the blood must be let when?

Answer 45

in 60 seconds(cattle) and
in 15 seconds(small ruminants)