Equine Castration Flashcards
why are horses castrated?
behaviour modification
management
control of breeding
medical reasons
how may castration aid behaviour modification?
reduces aggression
geldings are easier to handle
how can castration aid management?
can be turned out with mares
for what medical reasons may castration be performed?
neoplasia
trauma
cryptorchidism
what does cryptorchidism increase the risk of?
testicular neoplasia
when is castration usually performed?
when both testis have descended (6 months - 2 years in horses)
where can castration be performed?
field or hospital
who must legally perform castration?
vet
what are the anaesthetic options for castration?
standing sedation
GA
what are the 3 surgical techniques used for castration?
open
semi closed
closed
what happens during open castration?
vaginal tunic is incised and left open
what happens during semi-closed castration?
vaginal tunic is incised but subsequently sutured
what happens during closed castration?
vaginal tunic is sutured proximal to testis before incision
what is open castration used for?
standing field castration
when is open castration not used?
older horses
those previously used for breeding
donkeys
what anaesthesia is required for closed and semi-closed castration techniques?
GA
where are closed and semi-closed castrations usually performed?
hospital/clinic to maintain sterility
how can the decision to castrate in a field/hospital be affected?
facilities of practice and yard
possibility of transporting the horse
technique to be used
what affects whether standing sedation of GA are used?
size of horse (testis hard to visualise in small horses)
suitability for open procedures
temperament
cost
describe the process of open castration
incision made through the skin and vaginal tunic to expose testis
emasculators applied to vans defrens and testicular vessels
they are held closed for a period of time and then released gently
how do emasculators work?
crush vessels and cord (proximally) and transect distally
how many blades does an emasculator have?
2 blades
what is the role of the 2 blades of the emasculators?
one cuts, the other crushes
how should emasculators be applied to the vans defrens?
nut to nut!
why must you be careful when cleaning emasculators?
taken apart to clean and must be put back together so that ‘nut to nut’ is correct
how should emasculators be stored?
loosely and then tightened up before use
describe the process of closed castration
incision through skin only
blunt dissection of vaginal tunic containing testis from surrounding tissues
ligatures placed before emasculation
what are the main options for scrotal closure after castration?
sutured (primary closure)
left open (second intention)
with or without ablation
how is the scrotum left after field castrations?
open for drainage
what type of anaesthetic agents is standing castration performed under?
sedation with alpha2-agonist and butorphanol with local anaesthetic into scrotum and testicle
in what age animals is standing castration usually performed?
<18 months, well handled
what are the advantages of standing castration?
quick
effective
cheap
traditional
what are the disadvantages of standing castration?
poor asepsis
high incidence of minor complications
poor options for complication management
risk of injury to surgeon
what is the equipment needed for standing castration?
sedation analgesia (NSAID - injectable and oral) antimicrobials tetanus antitoxin gloves hibiscrub / spirit swabs / cotton wool local anaesthetic needles and syringes scalpel blade sterile swabs stitch kit suture material emasculators allis tissue forceps haemostats be prepared for GA - ketamine and IV catheters
how should a horse be prepped for standing castration?
sedate check for presence of 2 testicles scrub scrotum LA injected into the subcutis and testicle re-scrub the area
what is essential to ensure safety when palpating, prepping and castrating a horse?
safe positioning to ensure animal cannot kick surgeon
what position should horses be in for GA castration?
dorsal or lateral recumbancy
what equipment is required for hospital GA castration?
gloves scrub clippers urinary catheter gloves for tail and hooves drapes towel clamps surgical kit (as per standing) saline
what is required for GA castration in the field?
IV catheter
safe area to knock down and recover
how should horses be positioned during field GA castration?
lateral recumbancy with hindleg held up bay a lead rope
where should any assistants be placed during field GA castration?
by dorsal spine so out of kick/headbutt zone
what should be checked prior to castration?
age of horse
tetanus status
has it been used for breeding (affects technique)
facilities available at yard (e.g. water, stable)
two descended testicles (checked by vet)
what must be discussed with the owner prior to castration?
costs
risks/complications
procedure
what are the main complications of castration?
swelling haemorrhage (during or after) infection tetanus evisceration
what is the most common infection seen after castration?
schirrous cord
what is schirrous cord?
chronic staphylococcus infection of spermatic cord usually associated with ligatures
what is evisceration?
prolapse of omentum or intestine through inguinal ring
which is the most serious type of evisceration?
intestine - an emergancy
how can evisceration of omentum be managed?
resection
what should happen if evisceration occurs?
owner told to support intestine with clean towel
sedation
lavage
refurral to hospital for further treatment / surgery
what must be monitored for following open castration?
all potential complications excessive bleeding swelling anything protruding from surgical site appetite and fecal output
how much bleeding is expected following open castration?
drips expected for first 12 hours - should be able to count them
what bleeding from the scrotum after open castration will require intervention?
steady stream of blood
pulsating/arterial blood
what level of swelling is acceptable?
no larger than an orange or pre-surgical size
what effects of the sedation / anaesthesia must be monitored following castration?
appetite and fecal output
check for colic signs
what length of box rest is required following standard open castration/primary closure of scrotum?
24-48 hours
when is turnout permitted following standard open castration?
7-10 days post op
how often should horses be walked in hand in the days after standard open castration?
2-3 times a day
what is the benefit of in hand walking following standard open castration?
reduces swelling
encourages drainage
what is used for analgesia following standard open castration?
NSAIDs
for how long should recently castrated geldings be kept away from mares?
2 months post-op as they can remain fertile
what is cryptorchidism?
failure of testicular descent from the caudal pole of the kidney to the scrotum during embryonic development. Either retained inguinally or abdominally
how can cryptorchidism be diagnosed?
history palpation ultrasound blood tests surgical exploration
what blood test may be used to diagnose cryptorchidism in horses over 3 years?
oestrogen sulphate
anti-mullerian hormone
what blood test may be used to diagnose cryptorchidism in horses under 3 years and donkeys?
hCG stimulation
anti-mullerian hormone
what is the prefurred method for cryptorchidectomy?
laproscopic
what anaesthesia is required for cryptorchidectomy?
standing sedation or anaesthesia
what testis is laproscopic cryptorchidectomy more relevant for?
abdominal
when may ligation occur during laparscopic cryptorchidectomy?
internally or externally
