surgery - schultz Flashcards
4 routine Sx procedures performed frequently on food animals:
dehorning of cattle
dehorn goat / sheep
castration of calves
castration of piglet
what type of anesthesia is used for dehorning in cattle?
local - nerve block
what nerve block is used for de horning procedures in cattle?
cornual (zygomaticotemporal) nerve block
what is the landmark for the cornual (zytomaticotemporal) nerve block in cattle?
midway btwn the lateral canthus and the base of the horn
inject thru the frontalis muscle and under the lateral aspect of the temporal portion of the frontal bone
national recommendations suggest that cattle over what weight require anesthesia?
500 lbs
what type of anesthesia is used for dehorning anesthesia?
sedation AND local anesthesia
what nerves is desensitized in procedures to dehorn goats?
cornual branch of the lacrimal nerve
cornual branch of the infratrochlear nerve
where is the cornual branch of the lacrimal nerve loc in goats?
loc at the Cd ridge of the supra orbital process
where ist he cornual branch of the infratrochlear nerve loc in goats?
loc at the dorsomedial margin of the orbit
common local anesthetic used in goat dehorning?
xylazine
t/f
an alternative method for surgical dehorning is using caustic dehorning paste
true
when is it appropriate to use dehorning paste rather than surgical dehorning?
use on horn buds of young calves - horns that have NOT yet protruded from the skin yet
what is one caution to consider if the dehorning paste is used on young animals who are nursing?
they will bump their head on mom’s udder and the caustic paste will cause lesions on the udder
keep away from mom for about 12 hours
what tissue does the horn bud destroy?
eats tissue around the skin and epikeras
destroys the horny material
what instrument uses heat to dehorn?
dehorning irons
what is the power source for dehorning irons?
electric
gas
battery operated
any special considerations when using a dehorning iron on a goat?
goats have a much thinner skull than cattle
so only hold iron against head for 3 seconds to prevent thermal necrosis from occurring in the brain
how are scoop or tube dehorners used?
what age animal?
for newborn or young calves
push down and twist with the instrument
scoop out the horn or horn bud
risks using a scoop or tube dehorner?
you can push right through the thin skull of the goat if you are not careful
more opportunity for blood contamination here - can transmit BLV, anaplasma and other dzz - which would NOT be transmitted with a dehorning iron
what is a barnes dehorner?
how does it work?
what size horns is it best for?
for small to medium sized horns
the cutting end is located opposite the handle end
close the handles to open the cutting end up wide, place cutting end around the base of the horn, push down and push handles out, then pull it back out
what can be used to stop bleeding after useing a barnes dehorner?
electric dehorner
chemical powder
corn starch
hemostats
why can’t barnes dehorners be used on larger horns?
b/c higher risk you will open up a sinus if the horn is too big
what can be used for medium to large sized horns?
2 options
Keystone and electric keystone dehorners
dehorning saw or Gigli wire saw
how do keystone and electric keystone dehorners work?
cut tissue => do NOT crush skull
t/f
anesthesia is always used during large animal castration procedures
why or why not?
false
frequently NOT used
economics, convenience
when anesthesia is used for castration, what drug is often used and where is it applied?
lidocaine
injected into the spermatic cord (5-10 cc) and skin at the base of the scrotum
why do animals often bleed more after a lidocaine infusion?
b/c lidocaine causes vasodilation
what is typically administered at the time banding is done?
or 10-14 days before
tetanus vaccine
what size must testicles be to band?
any size - just use appropriate sized band
before castrating, what must you check?
make sure there are 2 testicles
where is a castration band applied?
above BOTH testicles
why is tetanus a concern after banding?
banding creates an anaerobic environment when it cuts off the arterial blood supply
tetanus is an anaerobic bacT and commonly infects the testicle after banded
how do you know if the bands you are using are tight enough?
as you are applying them, about 1 in 10 should break, telling you that you have enough tension when you stretch it
what is the mechanism of banders that leads to castration?
shuts off arterial flow so that necrosis and atrophy of the scrotum occurs
how long after banding will the scrotum fall off?
2 weeks
after the band is applied, the testicles should swell or shrink over the course of 14 days?
shrink
if they swell, you occluded venous flow and NOT arterial flow
it means that you did not put the band on tight enough
what is a birdezzo used for?
castration
how does a birdezzo work?
crushes blood supply and spermatic cord to cause atrophy of testicle
double crushes on each side
t/f
it is important to crush the median raphe with the birdezzo
false
do NOT crush the median raphe
why do you NOT want to crush the median raphe when applying the birdezzo for castration?
b/c it contains the blood supply to the scrotum and if you cut it off, then the scrotum AND testicles lose supply so nothing is there to contain the necrosis
the entire scrotum will fall off and leave a large gaping open wound
the band needs to stay intact to contain the necrosis and to seal the wound when the scrotum falls off
what 2 methods can be used for open castration?
knife cut
Newberry knife
how do you use a knife to perform castration?
hold bottom of scrotum, push testicles up, cut off bottom of scrotum and leave hole there
t/f
the newberry has 2 cutting surfaces
true
how do you apply the Newberry knife?
one hand pulls down on the bottom of the scrotum
2nd hand pushes testicles up
put the blade through tissue and then pull straight down
what does the cut with the newberry knife create?
separates scrotum into front and back halves to allow access to both testicles
does a knife cut castration or a newberry kinfe castration drain better?
why?
newberry drains better - b/c the edges of the cut are open more widely and the edges curve up - this remains open longer than a knife castration and is less likely to have infection
the knife cut produces a circular wound, which constricts and gets smaller as it heals, increasing chances for infection
during a pull castration, what structure do you want to pull and what structure do you want to NOT break?
pull the cremaster muscle
but: do NOT break the spermatic cord and vessels
how to apply an emasculator appropriately?
CRUSH THEN CUT
nut to nut (nut on emasculator applied in the direction of the testicle)
why do emasculators work better when they are just slightly dull?
b/c when the knife part is mor sharp, it is less likely to crush then cut - it may just cut right away, causing you to lose the piece
how does the henderson tool work?
what animals can it be used on?
spins to dec lumen of spermatic cord until it breaks off
any size - really good for large bulls b/c has little to no blood loss
what equipment is needed for a pig castration?
No 12 blade
strong holder or a V-shaped trough
what anesthesia is used for small piglet castration?
none
what anesthesia is used for large piglets and boars?
where is it injected?
IM barbiturae injection into 1 testicle
technique when castrating after barbiturate has been applied to one testicle?
cut off testicle without the barbiturate first, then the testicle with the barbiturate
pig wakes up soon after that.
