Ovine and Caprine Surgery Chapter 16. “It’s not that I’m so smart, it’s just that I stay...

Ovine and Caprine Surgery

Chapter 16

“It’s not that I’m so smart, it’s just that I stay with problems longer.” ~

Albert Einstein

Objectives

• basic differences between standing surgical procedures and general anesthesia procedures.

• Prepare a sheep or goat for surgery. • Assist and/or perform induction and maintenance of

anesthesia.• Provide anesthetic monitoring. • Manage the patient during recovery and immediate

postoperative periods. • basic risks and possible complications associated with

anesthesia and surgery, and implement preventive measures when indicated.

Key Terms

• Buck odor• Descenting• Elastrator• Fly strike• Hypoglycemia• Laparotomy• Malacia• Meningitis

• Supernumerary teats• Tetanus• Trocar• Urinary Calculi

Reading Assignment

Chapter 16: Sheep and Goat Surgeries

Surgery

• Similar to cattle– NPO: Food - 12 to 24 hours; don’t withhold water– Lambs and kids: consuming solid food material -

fasted for 2 to 4 hours.– Fasting is not recommended in neonates.• Low risk of regurgitation as rumen/reticulum not

functional• Hypoglycemia is common

Local Anesthetic

• Sheep, and goats especially, are more sensitive to lidocaine.– May be toxic at 10 mg/kg (cattle > = 13 mg/kg)

total dose.– Do not use in concentrations greater than 2%.• Dilute to 0.5 – 1%

– lidocaine toxicity: muscular tremors, severe depression, hypotension , occasionally convulsions

Blocks

• L block– Most common– A 18- to 20-gauge × 1 to 1 1/2 inches in length– Procedure same as cattle

• Paravertebral block: don’t need trocar– A 18- to 20-gauge × 1 1/2- to 3-in spinal needle– Use 0. 2 to 5 ml of lidocaine per site– Distal paravertebral approach: 20- to 22-gauge ×

1-in needle, 2 to 4 ml

Local Blocks

• Docking (~91 %), castrating (~78%), and disbudding are management practices routinely performed on sheep and goat farms.

• Maintaining a high standard of animal welfare shouldbe a consideration in all decisions related to docking, castrating, and disbudding.

Cornuectomy

Blocks (cont’d)• Cornual nerve block

– Goats: Dual nerve supply– Lacrimal nerve – cornual branch

– Depth: 1 to 1.5 cm– A 22- to 23-gauge × 1-in needle – 0.5 – 1 ml for kids; 2-4 ml adults

– Infratrochlear nerve – cornual branch– Depth: 0.5 cm– A 22- to 25-gauge needle – 0.5 ml for kids; 1-3 ml adults

– Sheep are rarely dehorned. – Lacrimal nerve – cornual branch

Anesthesia for dehorning in the goat. A, Needle placement for desensitizing the cornual branch of the lacrimal nerve. B, Needle placement for desensitizing the cornual branch of the infratrochlear nerve

Blocks (cont’d)

• Intravenous regional analgesia (Bier Block)– A 22- to 25-gauge needle– Up to 10 ml of anesthetic

• Caudal epidural analgesia– A 18- to 21-gauge × 1- to 1 1/2-inch needle for

caudal epidural– Not > than 0.5 – 1 ml of 2% lidocaine/ 50 kg. body

weight of sheep and goat

General Anesthesia

• Same concerns as with cattle• Inhalant gases

– Facemask induction < 150 lb– Oxygen (3 to 5 L/min) is given for 1 to 2 minutes before introducing anesthetic gas

• Halothane – 3 - 4%• Isoflurane – 3%• Sevoflurane 4 – 6%

• Endotracheal: 10 to 12 mm in adults – Heart rate: 80 to 150 beats per minute

• Pre – anesthesia: diazepam – ketamine - propofol

General Anesthesia (cont’d)

Long blade laryngoscope

Castration

• Usually done in week 1– Urinary calculi

• Can wait till 5-6 months in pets to reduce incidence of urinary calculi

• Castrate before sexual maturity• Adults– Hemorrhage– Sedated

Castration• Done in the same manner as calves with a blade• Age– Goats and sheep: 2 to 4 weeks of age– Pigs: 1 to 21 days of age

• Anesthetic– None is needed for sheep, cattle, pigs, or goats

• Should give tetanus antitoxin to goat and sheep• Can use antibiotics as preventative• Sheep and goats can be banded (emasculator bands)

• 10 days later

(cont’d)Emasculatone: spermatic cord

Emasculator bands

Castration – small ruminants

• Burdizzo emasculatome • Crushes the spermatic cord– which crushes the blood vessels

(thus depriving the testicles of blood supply) and causing them to shrivel up and die

• Don’t use cattle-size Burdizzo • By six weeks of age

Newberry Knife

Dehorning

US: dairy goats cannot be registered/ shown if they have horns

Disbudding: heat cautery

Dehorning (cont’d)

Tail Docking: Sheep

• Reasons– Improve sanitary conditions: Wool gets saturated

with urine and feces– Increase productivity in ewes: Tail will not get in

the way when bred– Appearance: Show animals

• Age– Before 2 weeks of age– Can do it 24 hours after birth if lambs are big

Tail Docking (cont’d)

– Reasons to dock early• Less trauma and stress• Less bleeding

– Types of tail docking• Sharp pocket knife• Emasculatone• Emasculator• Hot docking irons• Elastrator• Pruning shears

Tail Docking (cont’d)

• Procedure– Place tail on firm base.– Cut 1 inch from body.• Closer can cause prolapse

– Force skin toward body so excessive skin will cover end when done.

– Place the knife on the tail, and cut between the vertebra with a forward and downward motion.

– Spray with iodine.– Pinch dock between fingers, if excessive bleeding.

C-Section• Left flank with the female in right lateral recumbency• The head should not be elevated• L block• Clip and surgical preparation• Neonates

– Clear the airways– Confirm pulse and respiration– Dry and warm– Treat the umbilical cord

• Close with multilayer suture• Antibiotics and anti-inflammatories

Supernumerary Teats

• Serrated scissors– Cut craniocaudal

Descenting

• Removes buck odor– Rut : urinate head, beard, forelegs

• castration

– Primary scent glands • Caudomedial base of each horn

• Performed at any age• They may be removed during the dehorning procedure by

extending the skin incisions to include them. • At other ages: Under sedation and local anesthesia • Sutures can be used to close the skin• Breeding females may reject males that lack this scent.

Disbudding: The electric iron is now being used to destroy the scent gland areas on this male kid. The white arrow indicates the location of the second scent gland that will be burned next.

References

• K Holtgrew-Bohling , Large Animal Clinical Procedures for Veterinary Technicians, 2nd Edition, Mosby, 2012, ISBN: 97803223077323