Urogenital Large Animal BRAD Flashcards
What is the sedation/anaesthesia for small ruminant and bovine
Sedation
Small Ruminant
- Zoletil 100 (Tiletamine & Zolazepam): Short term procedures, IV/IM, onset 10min
- ZKX (Ket, Xylazine, Zoletil): IM/IV, Last several hours, gives 1-2hrs analgesia
Bovine
a) Standing: Xylazine +- Butorphanol & Ketamine: IV/IM +- Acetylpromazine: IV
b) Recumbent: Xylazine (x2) & Ketamine (x4-8): IV/IM
Anaesthesia
Bovine
a) Caudal Epidural - 2% lignocaine HCL: C1-2, 18G 1.5inch
Prevents ab contractions but NOT suited for C-section & shouldn’t affect motor control
b) Local Anaesthetic
Paralumbar Laparotomy
- Paravertebral: T13-L3, 20-18G long, 10ml above & below transverse processes
Dis: ↑ technique & time till effect
–> hard in well-conditioned beef cows
- Line or Inverted L: Toxic dose Lignocaine HCL – CS of systemic toxicity
Describe small ruminant urolithiasis
Hosts: Castrated males, occasionally intact males
Cause: Dietary and management related
PF:
- High concentrate ration
- Low fibre/ roughage
- Incorrect Ca:P ratio
- High Mg diet
- Alkaline urine
- Long/convoluted/narrow urethra
- Texel & Scottish blackface (breeds)
Aetiology:
Aetiology:
- Phosphorus is recycled through saliva & excreted in faeces
- High grain/low roughage diets ↓ saliva production → ↑ Urinary P excretion
- Increased urine output (If acidic) can prevent formation of uroliths
Site of Obstruction: Most lodge at Urethral process! (N/A in alpacas), second most common is Distal sigmoid flexure
Multiple small uroliths in bladder and along urethra
CS:
- Bleating/vocalising
- Haema/dys/stranguria
- Tail flagging
- Ab pain (Stretch limbs)
- Recumbency
- Preputial & ab swelling
- subcutaneous oedema
- Seizure, cadiovascular collapse
- Death
What are the types of calculus?
Calcium Carbonate: Small gold beads, pastures high in clover or oxalate containing plants
Struvite: Sand-like Mg ammonium phosphate,
High PO4 or Mg diets – common in feedlot/high grain
Apatite: Ca-PO4, high Ca & oxalate intake
Silica: Semi-arid region
How to diagnose, prevent and treat urolithiasis?
Dx:
- US
- Radiography
- Biochem: ↑ BUN (Blood Urea Nitrogen) /creatine/elevated muscle enzymes AST/CPK, Hyper/normokalaemia, hypoNa, hypoCl, acidosis
Prevent:
- 2-5% (30g/day) Dietary NaCl or AmmoniumCl (0.5-1%) / 10g/day
- Low K & Ca diet
- Ca:PO4 2:1 (Grass hay 1:1, Lucerne 5:1)
- DON’T use horse feed
- +-? Castrate >6m –? allow development of normal urethral diameter.
Treat:
- IV catheter & fluids
- Sedate: Diazepam +- ketamine & Oxygen + isoflurane as needed
–-> AVOID xylazine (Hypotension & sleepy) - Insert Allis forceps into preputial cavity → Grasp & pull-out fold → Repeat until penis everted
- Sx:
Ex-lap, cystotomy: evacuate bladder calculi. - retrograde lavage of bladder and urethra using urinary catheter, tube cystotomy +- Perineal urethrostomy if obstruction distal to sigmoid flexture
- Non-Sx:
Grasp penis w/ gauze → Amputate urethral process & wait for re-obstruction (70-80% do) → Insert sterile polypropylene Rutner catheter (5-10) retrograde → Lavage bladder w/ warm saline & Renacidin (Mg-Carbonate, Citric acid – 2x daily for 2 weeks) - Retrograde Catheterisation: Urethral diverticulum at ischial arch prevents retrograde passage into urinary bladder – NOT recommended as unsuccessful/further trauma of the uretha
How to do a Cystotomy?
Method:
- Exteriorise penis, resect urethral process, insert 5-10 polypropylene catheter retrograde to the diverticulum or obstructing stone
- Place slip knot of sterile tensofix around glands w/ long ends to allow extension of penis during surgery
- Caudal ventral midline incision → Pack intestines with lap sponge & exteriorise bladder
- 1-2cm incision at bladder apex → suction urine → Explore & remove large stones
- Smaller stones removed w/ catheter tip syringe & suction tube to suck out calculi
- Pass catheter normograde & lavage bladder to empty urethra, catheters should pass easily once urethra is cleared
- Lavage/incise penis over calculi & remove
- Suture urethral incisions at urethra & tunica albuginea w/ 4-0 Vicryl/monosyn simple interrupted pattern w/ catheters in place to avoid incorrect suture placement.
- Anchoring sutures btwn tunica & fascia of caudal thigh → then urethral mucosa to skin SI (simple interrupted) sutures
What is tube cystotomy?
Method:
- Move bladder to one side of laparotomy incision & mark where apex of empty bladder contact’s the body wall
- Stab incision (0.5cm) in skin/wall ~3-5cm from edge of midline incision
- Insert 24 Foley catheter through stab wound & thread tip into cystotomy incision
- Suture bladder w/ SI 1-0/2-0 Vicryl, last suture should be close to catheter entry and seal the hole.
- Place purse string suture around catheter inside bladder & as the purse string is tightened, invert original linear incision and entry site of the Foley catheter.
- Fill Foley balloon w/ saline & distend bladder to check for leaks → Rx last step & re-test
- Once bladder is sealed, pull bladder to peritoneum at entry of foley & suture in place via purse-string
- Place condom over end of foley for 1 way valve & close ventral laparotomy incision
- Maintain tube cystostomy until urine dripping from prepuce for 48hrs → Clamp & monitor urination
- Removed: Able to urinate, empty bladder, no pain Left for 5-7d: Partial urination
Advantages and disadvantages of tube cystostomy?
Px: 80% good prognosis
Adv:
- Maintain breeding function in intact males
- Don’t have to remove all small calculi
- Avoid risk of stricture formation with Perineal urethrostomy
Dis:
- Increased cost
- Re-obstruction is possible
What is a Perineal Urethrostomy?
Indication: All patients with a ruptured perineal urethra
Methods:
6cm Incision on midline of perineum ~4-6cm ventral to anus and either:
a)
- Penis is elevated to incision & stay sutures (0 PDS, vicryl) are placed btwn perineal fascia overlying semimembranosus m. & tunica albuginea of the penis
- 2cm Incision on caudal & ventral midline of penis (Over urethral groove)
- Tunica albuginea is sutured to SC tissue adj/ to skin (0 PDS, vicryl)
- Urethral mucosa is sutured to skin edges of wound (3-0 monosyn, 4-0PDS)
b)
- Penis is dissected ventral to incision & proximal stump exits wound
- Stay sutures placed circumferentially around penis from tunica albuginea to skin
- Urethral mucosa is sutured to cut edge of tunica albuginea
Complications:
- Urine scalding (Too prox. To perineum)
- Haemorrhage post-op
- Stricture (Esp. young)
- Rx obstruction (50-70% <1yr)
Describe urine pooling in cows
Consequences: Significant cause of infertility due to incompetent constrictor vestibuli m.
Method:
A) Caudal Urethral Extension
- Foley catheter placement in urethra
- Create/invert/Connell pattern suture 2 lateral mucosal flaps parallel to catheter
B) Vestibulovaginal Cerclage Suture Technique:
- 2x PDS purse-string around vulvo-vestibular junction, caudal to urethral fold
- Tightened so only 1 finger can be inserted in vagina
- Resolved in 89% cows, Pregnancy rates 74% vs 35% in control
What are the reasons to castrate production animals?
- Tractability, handling and management practices
- Prevent unwanted breeding
- Promote weight gain
- Correct scrotal/inguinal hernia
- Testicular malignancy, orchitis, abscess or injury
Castrate:
- Calves < 2 months
- Pigs, sheep, goats 2 weeks
- Camelids
- Camels
How to do a small ruminant castration?
- Diazepam +- Ketamine IV & lignocaine at testis/cord, meloxicam PO (Orally)/SC
- Lateral recumbency w/ tied leg OR DR (Dorsal recumbency), clip/aseptic prep/drape distal scrotum
- Incise distal 3rd of scrotum & strip out testis until 5cm cord is showing
- Incise parietal tunic longwise down the exposed spermatic cord
- Expose pampiniform/vas deferens via inserting Kelly haemostats into the tunic incision and apply transfixation ligature to pampiniform and vas deferens. (0 Vicryl/Monosyn)
- Transect/emasculate testicle & ligate cord/tunic 1-2cm proximal to other ligature
What is a hemicastration?
Indication: Orchitis, scrotal hernia
- Incise long axis of scrotum parallel to testicle
- Vaginalis opened for inguinal reduction BUT closed in most bulls to ↓ time/risk of hernia
- Open: Spermatic cord is ligated individually
- Closed: Combo of emasculation/transfix ligation of spermatic cord
- SC & tunic closure, pack w/ gauze → DON’T close skin as it may cause excess fluid & swelling
How to do a calf castration?
- Xylazine +- ketamine & incise on side of scrotum → open or closed ligation
- Horizontal incision: Better drainage
- Ventral: Must go from caudoventral to cranioproximal to prevent edges healing too quickly
How to do a South American Camelid Castration?
- Xylazine & Ket IV/IM, Atropine if HR <30bpm, DR (dorsal recumbency) w/ head to one side and towel under neck to prevent Aspiration
- Clip & drape → 2x Pre-scrotal incisions & push testes cranially → Open or closed. Ligate pampiniform plexus and vas deferens then tunic
- Leave scrotal incision open to heal via 2nd intention & give tetanus prophylaxis, PPG, Flunixin
How to do a piglet castration?
- Xylazine, Ketamine & Butorphanol IM, 10m till effect, lasts for 30 minutes, Cradle or DR
- Closed technique & transfixation ligatures, watch for herniation
