Chapter 16 Ovine and Caprine Surgery

“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.

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

Key Terms

• • • • 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 should be 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

Emasculatone: spermatic cord

(cont’d)

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