Porcine Anaesthesia, Surgery and Patient Care Flashcards
What are some common surgical procedures in Pigs?
MAIN ONES:
- Castration
- Hernias
- Tail docking
- Tooth clipping/ tusk trimming
ALSO:
- C section
- Rectal prolapse
- Digit amputation
- Wound/laceration repair
- Entropion
- OVH
- Aural hematoma
What considerations for cost & welfare?
- Boars and sows of high genetic merit
- Pet pigs
- Potential risks and prognosis
- Aftercare - beware mixing with other pigs
- Tehcnical difficulties - on farm
- Commercial v pet pigs
ensure: written consent & costs discussed
Pet pigs?
Vietnamese Pot-Bellied, Kune Kune, Gloucester Old Spot, and the Tamworth.
Owners may place a high value on these animals
Commercial pigs?
- Relatively low value
- Procedures may not be cost-effective
High genetic merit pigs ?
High-value procedures maybe cost effective
General Surgical Considerations in swine?
- Thermoregulation
- High portion of body fat
- Malignant hypothermia
- Analgesia
- Variable response to sedation
- Anaesthesia
- Local anaesthetic
- Intubation difficult
- BW
- Vascular access
- Restraint & handling
Describe multimodal analgesia in pigs?
What agents do we use for what?
Describe Azaperone
- 1-2mg/kg deep IM
- Light- mod sedation
- Low dose in boars intended for breeding
- Leave alone to work
Licensed
Uses of azaperone?
- Aggression (prevent fighting)
- Stress, incl transport related stress
- Obstetric conditions
- PRemed in local and GA
What ALpha 2 agonists can we use?
- Xylazine 1-3mg/kg IM
- Detomidine 0.1mg/kg
Use of ALpha 2s?
sedative with some analgesic and muscle relaxatn properties for use in cattle, horses, dogs & cats
premed for minor operations
Ketamine for induction?
- 15-20mg/kg IM after Azaperone pre-medication
- 5mg/kg IV
- Lower doses if using two drugs for premed
- High doses ass muscle rigidity
- 40 mins of anaesthesia
KEtamine licensed?
Yes for 15-20mg/kg Off license at lower doses
Maintenance with ketamine?
5mg/kg IM or IV
Q 30 mins after induction
ketamine used with what?
with xylazine in horse cattle dog and cattle
with azaperone in pig
Tail Docking - Pigs?
“only carried out where measures to improve environment conditions”
An anaesthetic and additional
prolonged analgesia must be administered where the animal is aged 7 days or over.
Tooth reduction (clip)
uniform reduction of the corner teeth by either grinding or clipping to
leave an intact smooth surface
The procedure may only be carried out on an animal that is aged not more than 7 days.
Tusk trimming?
may only be carried out where there is evidence to show that it is necessary to prevent injury to other
animals or for safety reasons.
Castration?
The method used must not involve the tearing of tissues. An anaesthetic and additional prolonged analgesia must be
administered where the animal is aged 7 days or over.
What regulations around Pigs?
DEFRA -Code of practice for the welfare of Pigs (2020)
The Mutilations (Permitted Procedures) (England) Regulations 2007
-> tail docking, castration of pigs can be carried out by vet surgeon or when not more than 7 days by experienced person
Pre-op considerations castration of piglets?
Is analgesia required for castration?
NO for less than 7 days old
baby pig castration - how did it used to be done?
Restraint > suspended by the hind legs
Preparation >The surgical site is prepared aseptically
Anaesthesia>Local anaesthesia used
Procedure ->Open castration
Incision skin/tunica vaginalis.
Gubernaculum broken
Spermatic cord broken by traction, testicle removed.
After-care
> Topical antibiotic spray
>Systemic antibiotics are rarely used.
>Creep under a heat lamp
Inguinal hernias and undescended testicles may be found at the time of surgery.
why do we castrate?
Usually done to avoid unwanted mating, aggression & odor following puberty
How to - castration in pigs?
Beforehand -> check for inguinal hernias in miniature breeds
Age: castrate pig between 2 weeks and 3 mo
Beware: hypoglycaemia & hypothermia
Anaesthesia:
- Deep sedation & local anaesthesia or GA
- Technique -> closed
Describe the procedure ?
Dorsaly recumbency
- Incise skin (testicle extended over inguinal ring)
- Tunica vaginalis maintained
- Gubernaculum broken
- Spermatic cord ligated & cut below ligature
- Remove testicle
- Horizontal mattress suture inguinal ring
Skin sutures (non absorbable)
What else to give during castrate?
ABs topical and systemic
Analgesia
Prophylactic anti-toxin tetanus?
What aftercare for piglet Castrate?
- Keep warm until recovery is complete
- shelter and bedding provided for next 24hrs
How to castrate in commercial boar
- Scrotal incison over length of testes
- Tunica vaginalis incised over testicle
- Gubernaculum ligament manually broken down
- Tunica vaginalis reflected up the spermatic cord
- Crush spermatic cord w/ forceps then place distal to crush site
- 2 absorbable transfixion ligatures placed around spermatic cord proximal to forceps in the crush site
- Spermatic cord is held with rat-tooth proximal to lig & sever
-check bleeding
leave scrotal skin open
Mature boar - aftercare?
- Pig should be kept confined in small pen with clean straw for 7-10day
- Boar taint will dissipate over 6-8 weeks following castration if done in mature boars
Same complications as surgical castration in other species ?
- Haemorrhage
- Infection - high in older animals
- Risks of anaesthesia
- Difficult to get accurate doseages
HERNIATION -spontaneous inguinal hernias
Describe Hernias?
- Most common genetic defect
- Inguinal or Umbilical
- both more common in males
Primary genetic vs neonatal ophalitis
Patient choice hernias?
- Cost of procedure - commercial unlikely to fix
- Some may get to slaughter without problem
- Size of hernia, size of defect, likelihood of successful correction
Hernia - anaesthesia & analgesia?
Anesthesia or deep sedation + LOCAL
NSAIDS - meloxicam licensed IM & Oral
ABs for hernia surgery?
Abdo surgery non-sterile -> give …
do we tend to repair umbilical hernias?
not cost-effective in commercial - small hernia left untreated
What to do for reducible inguinal hernia?
Testicle is exteriorised ; sperm cord massaged and twisted
Force contents back into peritoneal cavity
Twisted sperm cord/ tunica vaginalis ligated and testicle removed
Horizontal mattress suture closes inguinal canal
What to do for irreducible inguinal hernia?
- Open tunica vaginalis break down adhesions broken down
- Try to replace contents into peritoneal cavity
If impossible -> inc size of inguinal canal by cutting cranial border of ring with repair of scissors
If still impossible what else can we do for inguinal hernia?
- Paramedian abdo laparotomy
- Contents of hernia can then be pulled back into abdo
- SPerm cord ligated and testicle removed
Regardless of technique what should be done with inguinal hernias?
CLOSE the inguinal canal with a mattress suture
Why do we tend to do C-setions in pigs?
- Dystocia uncommon
- Sows with dystocia likely exhausted
- Large piglet/ uterine inertia
- Under GA
What surgical approach things to remember with C-section?
- Lateral recumbency
- Exteriorise uterus easily
- Incise as close to bifurcation as possible
- Milk piglets down the horn to the incision and remove
- Need to close in more layers than cattle/ sheep
PAtient choice C-Section?
Sucess rate ?
Longer labour = poorer pg
Sow exhausted & possibly toxaemic
Anaesthesia for C -section?
GA recommended
Support with IVFT +/_ glucose (via ear vein) and NSAIDs
Site for C-section?
Suppramammary ventrolateral approach
Position sow in lateral on floor, upper limb elevated and moved backwards
Describe laparotomy to remove piglets?
- Partially exteriorized
- 6-8cm incision long axis of uterine horn
- As close to the bifurcation of uterine horns as poss - facilitates removal of piglets
Pt 2 of C-section protocol?
Try to extract the piglets from the other horn
uterine wound closed inverting sutures absorbable material
horn replaced into the peritoneal cavity.
Repeat other horn if neccissary
Always examine the uterine body and vagina caudally to ensure no piglets are missed.
Warm saline may be used to lavage the uterus to reduce the risk of adhesions.
What four lines to close abdomen?
(1) the peritoneum and the transversus abdominis muscle
(2) the internal and external oblique muscles
(3) the subcutis and fat
(4) the skin.
What can we give with a C-section?
- Post op ABs & analgesia
- Oxytocin once surgery done to facilitate uterine involution
- Skin sutures removed in 14 days
Describe Uterine Prolapse in pigs
- Immediately or within several days of parturition
- Poor pg
- 1or 2 horns affected
- Complicated replacement due to length of horns
- PResentation ranges from unaffected to shock
- Under GA or heavy sedation. + Epidural
what to do if can’t replace?
Uterine amputation
How do we replace a prolapse?
- check for lacerations
- Wash
- Apply sugar/electrolyte powder to reduce oedema
- Lubrication not recommended
- Replace horns progressively starting at vulval lips
- Instil 3L sterile saline into horns after
- Admin oxytocin to encourage involution
(lateral laparotomy to pull uterus into and is possible)
what might have happened if sow found dead from prolapse?
haemorrhage of uterine arteries
how to position the sow if prolapsed uterus?
sternal recumbency with hind quarters elevated
Why do we do amputation of prolapsed uterus as salvage procedure?
TO preserve sow until piglets weaned
Haemostasis for amputation?
- Base of uterus surrounded with overlapping mattress sutures
- Sutures full thickness of uterine wall and be tied tightly
- Monofilament nylon is usually used
Describe uterus amputation?
- Two anchor pins
- Distal uterus amputated distal to mattress line
- Ligation of bleeding vessels
- Removal of anchor pins
- Uterine stump replaced into the pelvis
some clinicians do SC purse string suture around vulva
Describe Tail docking
- Only where recognised problem
- <7d
- No anaesthetic used
- Emasculators to crush and scalpel used to remove tail / sharp pliers
- remove no more than 1-2 cm from base to avoid rectal prolapse in later life
- tail biting associated with poor enrichment
Describe Tooth clipping?
- Only when recognised problem
- Canine teeth
- Prevent injury to sow and other piglets
- > 18hrs to not disturb collosturm intake
- teeth cut back to gum line
- Fracture of teeth/damage can cause infections etc
Describe Tusk trimming?
- Complete removal of canine teeth (tusks) is difficult
- Restraint by a snare or deep sedation/ general anaesthesia
- A length of embryotomy wire with a handles on each end
- cut just above gum margin above pulp cavity
- Edges of tooth rasped to remove sharp bits
- Depending on growth rate risks may have to be cut every 6-12 months
risk factors to rectal prolapse
DIarrhoea, short tail, excessib-ve huddling an piling, excess mating/riding, parturition
CLS of Rectal prolapse?
Tenesmus, everted mucosa through anus
Tissue becomes oedematous damaged and revitalized
Tx options for rectal prolapse?
- Replacement an application of sphincter purse string suture
- Prolapse amputation
Tx for mild cases?
- Epidural
- Reduction by lubrication an gentle massage of prolapse
- Purse string suture
LEft in place 7-10 days
What options for Severe cases?
- Tube and contriction elastrator ring
- Surgical resection
Describe tube and constriction elastrator ring?
- GA
- Sedation & lumbosacral anaesthesia ; local perianal infiltration
- Tube plus tight rubber ring
- necrotic tissue, ring and tube fall off after 3-7 days
- Xylazine in epidural will reduce renesmus for a period of up to 24 hrs
- Complication rectal stricture
Surgical resection?
Time consuming
Anchor prolapse
Surgical excise prolapse
Suture mucosa
Complications of severe rectal prolapse?
- fibrosis / stricture
- Difficulty passing faeces
Conditions that may require digital amputation?
Severe infections of the foot
Osteomyelitis
Septic joints
Procedure for amputation (digital)?
- High digital / claw amputation
- Remove third and second phalanges
Tournequet -> incise skin -> amputate -> dressing -> analgesia & antibiotics -> remove tourniquet
Aftercare for amputation?
Kept in well bedded pen for 3-4 weeks
Dressings removed in 10 days
Describe Aural haematoma?
- LArge fluctuant swelling of ear
- Needle aspirate serum or unclotted blood
- needle aspiration using snare
- LAncing
ABs to not have infection
Describe entropion
- Frequent in pot-bellied pigs
- Lower lig but can be both
- Unilateral or bilat
- Ga surgery tx
Describe the surgical procedure for entropion.
- Pair of forceps placed 3-5 mm below/ parallel to lower lid margin
- Test length and width of skin held between jaws of forceps
- Position of forceps adjusted so entropion is resolved without ectropion
removal of skin -> with scalpel
CLOSE with PDS suture
Procine Fractures?
- Rarely cost effective to repair
Euthanase
OVH in pigs?
- Increasingly popular
- Control bhvr
- Prevents uterine/ ovarian disease
- note: more vascular broad ligament than dogs
When would we do OVH?
4-8 months
What recumbency for OVH?
Dorsal -> GA
