bovine surgical procedures key terms: casting, cosmetic dehorning, hemostasis, horn button, myiasis,...

Bovine Surgical ProceduresKey Terms: Casting, Cosmetic

Dehorning, Hemostasis, Horn Button, Myiasis, Scur, Supernumerary teats,

tipping

Chapter 12

Objectives

• differences between standing surgical procedures vs. general anesthesia procedures.

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

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

postoperative periods. • Understand the basic risks and possible complications

associated with anesthesia and surgery, and implement preventive measures when indicated.

Bovine Surgery

Chapter 12: Bovine Surgery

• Valuable animals– High producing dairy

female– Registered breeding

stock– Pet animals

Jan 2010: A two-year-old Aberdeen-Angus bull has been sold to an American buyer for what is believed to be a UK record price of 75,000gns

Bovine Surgery

• Standing– Lacerations/ punctures– Castration, c-section– LDA/ RDA– Enucelation, dehorning– Distal limb injuries

• General anesthesia• Heavy sedation and

casting– Limbs and feet

After opening the sterile pack of surgical supplies and draping the cow, the patient is ready for a standing cesarean section via the left flank

Utrecht (1975)

LDA

• Rumen– inspection, palpation– auscult – frequency &

character• Ping (fluid-gas)

– Abomasum: LDA– Rumen: normal unless

otherwise (palpate for rumen)

– 1-3/minute• 1º rumen/reticulum• 2º rumen only

Preparation for Bovine Surgery

• Facility: clean, dry and draft free• Sedation/ tranquilizers– Depress GI motility > bloat/ ruminal tympany– Regurgitation

• Withdraw food: 12 – 24 hours• Withdrawal water: 6 hours

• Local anesthesia/ blocks: in addition to sedatives– L Block, paravertebral block, cornual nerve block, IV

regional analgesia, caudal epidural analgesia

Preparation for Bovine Surgery

• Local Block Drugs– Lidocaine (cheapest and safest)• lidocaine toxicity: muscular tremors, severe

depression, hypotension , occasionally convulsions• Toxic dosage: > 13cc of 2% lidocaine per 100 lb or > = 13 mg/kg

– mepivacaine, bupivacaine– Withdrawal time

L Block

• Used for standing flank laparotomies• Most common• Procedure– Complete surgical prep.– Place anesthetic in an inverted L configuration using a

18 × 1 1/2- to 3-in needle.– Anesthetic is placed: SQ, muscular layers– Amounts of anesthetic: 60 – 100 ml of 2% lidocaine

for adult cattle– Allow 10 to 15 minutes to take effect.

Paravertebral Block

• Use– To create a large flank anesthetic zone• Skin to peritoneum

– Blocks T13, L1, and L2

• Prep – Surgical prep

• Procedure – Two approaches: Dorsal and lateral

Paravertebral Block (cont’d)

• Dorsal approach/ Farquason or Cambridge method/ proximal paravertebral method– Near the intervertebral foramina– A 16- or 18-gauge needle, 3 to 6 inches in length

• A 18- or 20-gauge for smaller ruminants – Or placement of a 14-gauge × 1-in needle first and then insert an 18-

gauge needle through the 14-gauge needle

– Place 20 ml per injection site • Use 2 to 5 ml for sheep and goats

– Block: skin to the peritoneum, including the longissimus muscle– Can create a temporary curvature of the spine (scoliosis, because of

blocking lingissimus m.) , making it difficult to close the incision


• Lateral approach/ distal paravertebral method/ Magda or Cornell method– Near the tips of the transverse processes of the

lumbar vertebrae– A 18-gague × 1 1/2- to 3-in needle • 20-22 gauge × 1 for sheep and goats

– Use 10 to 20 ml per injection site • Use 2 to 4 ml for sheep and goats

Cornual Nerve Block

• Use – Desensitization of the horn and horn base

• Preparation– Surgical preparation

• Procedure

– Cattle – Goats

Cornual nerve: blocked halfway between the lateral horn base and the lateral canthus of the eye, horn is continuous with frontal sinus

Cornual Nerve Block (cont’d)

• Single nerve• Amount and depth– Calves: 3 to 5 ml, 1 cm– Adults: 5 to 10 ml, 2.5 cm (large adults)

• A 18- to 20-gauge × 1 to 1 1/2-in needle• Well developed horns in adults: 2nd injection

on base of horn and caudal aspect under the skin

Intravenous Regional Analgesia (Bier Block) • IV analgesia is considered superior to local nerve blocks/ ring

blocks for most surgical procedures of the distal extremities.

• Preparation – Surgical preparation

• Procedure – Restrain, sedate, and cast.– Apply tourniquet: Padding should be in place underneath.

• Cotton/ foam padding• For feet procedures, place at midcarpus or midtarsus.• For proximal procedures, place just proximal to carpus or tarsus.

Intravenous Regional Analgesia• Procedure– Inject IV into any large superficial vein.– Dorsal metatarsal/ metacarpal vein– Plantar/ palmar MT/MC vein

– Cattle: 18- to 20 G– Small ruminants: 22- to 25 G– Use 10 to 30 ml: 2% lidocaine/ mepivacaine– Wait for 10 to 15 minutes.– Do not leave tourniquet in place for longer than 2 hours.– Slowly release tourniquet: anesthetic wear off 5 to 10 min.

Caudal Epidural Analgesia• Common in obstetrics and prolapses: uterus, vaginal, rectum• Blocks: anus, perineum, vulva, caudal vagina,caudal aspects -

thighs• Preparation

– Surgical preparation• Procedure

– Placement on the dorsal aspect of the tail base at the first intercoccygeal space; the sacrococcygeal space is less common

– Palpate tail up and down for proper placement.– A 18 × 1 1/2-in needle at a 45-degree angle.– Use 1 ml/100kg: 2% lidocaine, mepivacaine, xylazine– Allow 10 to 20 minutes for effect; lasts 1 to 2 hours.

CAUTION: can cause HL ataxia with too much anesthetic

Cranial epidural: L-S space are not common: difficult to perform, posterior paralysis “splay legs”

• For prolonged anesthesia: small diameter epidural catheter• DA: kinking catheter/ plugged with tissue/ fibrin

General Anesthesia• Anesthetic risks: uneventful

recoveries– Prone to regurgitation

• Aesthetic drugs relax smooth muscle

• Aspiration pneumonia• Withdraw food and

water• Cuffed ET tube• Quick intubation• Don’t roll ruminants

Preputial surgery: http://www.drostproject.org/en_bovrep/12-56/itemtop15.html

General Anesthesia (cont’d)

General Anesthesia• Anesthetic risks

– Prone to distention of the rumen (bloat)• Fast• Have equipment ready in case

you have to treat

– Prone to hypoventilation• Fast• Appropriate anesthetic depth

– Compartment syndrome• Myopathy, neuropathy• Padded stall

• Uneventful recoveries


• Preanesthetic preparation– Preanesthetic evaluation: PE– Preanesthetic drugs • Acepromazine : Phenothiazine derivative. Calms animal–Prolonged penile relaxation–2 -4 hrs. tranquilization (not great tranquilizer)–Don’t use in dehydrated patients: hypotension


• Preanesthetic preparation – Xylazine: use 20 mg/ml; alpha2 agonist• Dosage: 0.05 – 0.1 mg/kg IV; 0.1 – 0.5 mg/kg IM• Very sensitize: 1/10 dose; Hereford/ Brahman • Effects: bloat, bradycardia, resp. depression,

hyperglycemia (osmotic diuresis); uterine contractions (premature labor); transmammary transmission• Reversal: Yohimbine, Tolazoline


• Preanesthetic preparation– Detomidine/ Medetomidine: alpha 2 agonists• Reversal: atipemazole

– Anticholinergics: atropine, glycopyrrolate• Antisialogues• Reduce incidence of bloat


• Induction Drugs: – Inhalant gases (< 150 lb. face mask: halothane: 3-4%;

isoflurane: 4-6%; sevoflurane: 4-6%)– Thiobarbiturates: not is < 3 months, crosses placenta– Ketamine: combo with xylazine or acepromazine– Guaifenesin: combo as muscle relaxant; not > 5%:

hemolysis; triple drip: xylazine/guaf/ketamine bit has cardio and resp .challenges

– Telazol: tiletamine – zolazepam; calves and small ruminants

– Propofol: anesthesia for 10 minutes


After induction than pass et TUBE•Direct visualization: laryngoscope, sternal recumbency: stylet•Palpation of epiglottis

KNOW table 12 -1 and 12 -2

DON’T USE Nitrous oxide

General Anesthesia (cont’d)• Maintenance of anesthesia

– Short: injectable drugs/ inhalants and long procedures > 60 mins. : general anesthesia• Depth

– Ocular reflex: corneal reflex has to be present and palpebral reflex is delayed

– Eyeball position» Light: ventromedial» Deep: central

– Pupil size: mydriasis: overdose of inhalant

– Muscle movement: none when scalpel is used

• Monitoring of anesthesia– Ventilation

» RR and tidal volume (depth): 20-40 / min.

» Mm color» Blood gas monitor

– Circulation» Pulse strength: coccygeal,

median, auricular, femoral» Mm» CRT» HR: 60-120 bpm

– BP: MAP > 70 mm Hg if less than 60 hypotension

– Monitor temp.


• Fluids– IV fluids : LRS: 5-10

ml/kg/hr.; neonates may need dextrose

– Oxygen supplementation• Recovery: usually eventful– Start with 100% oxygen– Sternal recumbency– Remove tube after

swallowing reflex with partial cuffed ET tube

References

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

• http://www.drostproject.org/• http://www.cvmbs.colostate.edu/clinsci/

callan/bovine.htm• http://www.farad.org/index.asp• http://informedfarmers.com/control-and-

prevention/

bovine surgical procedures key terms: casting, cosmetic dehorning, hemostasis, horn button, myiasis,...

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