La Surgery Packet 8

Front 1

description of castration

Back 1

removal of testicles or actions taken to cause testicular degeneration resulting in reduction or lack of testosterone secretion

Front 2

indications for castration

Back 2

- remove less desirable traits from gene pool
- reduce management problem: fighting injuries, better pasture management, prevent pregnancies
- improve meat quality in pigs and beef
- arrest scent gland development in goats

Front 3

negative factors of castration

Back 3

decreased rate of gain and feed efficiency: steers must be fed longer to have the same carcass quality (can be corrected with use of implants or trenbolone acetate and estradiol)

Front 4

suggested age for castration as a general rule

Back 4

can be performed at any age but hemorrhage is greater problem in older animals and herniation is a greater problem at younger ages

Front 5

suggested age for castration in equine

Back 5

most horsemen wait until the colt is around 2 years of age: masculine conformation has developed at this time and testicles are usually in the scrotum

Front 6

suggested age for castration in bovine

Back 6

- usually performed on animals less than 500 lbs
- the younger the animal, the less the stress but early castration associated with some increase in urethral calculi problems

Front 7

suggested age for castration in ovine, caprine and porcine species

Back 7

usually performed during the first 2 weeks of life

Front 8

pre-operative conditions for castration

Back 8

- animals should be in good physical condition
- general husbandry and owner's ability to manage animals post-surgery should be evaluated (clean, dry area with no access to sweet clover)
- testicles should be evaluated, external inguinal ring should be of normal size

SURGERY SHOULD BE DELAYED IF CONDITIONS ARE NOT RIGHT

Front 9

advantages of colt standing for equine castration

Back 9

- performed more rapidly
- no chance on injury when animal going down or getting up with anesthesia
- anesthetic complications are reduced

Front 10

disadvantages of colt standing for equine castration

Back 10

- increased chance of injury to surgeon
- restraint not as reliable
- surgical complications are more difficult to manage

Front 11

restraint for standing equine castration

Back 11

- physical restraint: lead rope and twitch
- sedatives

Front 12

sedatives used in equine castration

Back 12

- xylazine
- ace + xylazine
- ace + xylazine + Talwin
- xylazine + morphine
- xylazine + butorphanol
- detomidine
- butorphanol
- romifidine

ACE CAN CAUSE PENILE PARALYSIS

Front 13

chemical restraint for recumbent equine castration

Back 13

current anesthetic regimen is premed with ace/morphine, xylazine followed by ketamine or glyceryl guaicolate and surital/thiopental or ketamine

Front 14

bovine restraint and anesthesia for castration

Back 14

- larger animals routinely castrated standing: restrained in chute with head in a head catch and tail firmly held over back
- recumbent routinely used for small calves: calf cradle
- anesthesia not commonly used in N. America
- testicle or spermatic cord can be infused with local anesthetics
- anesthesia of the skin of the scrotum can be produced by infusing local anesthetic subcutaneously

Front 15

ovine and caprine restraint and anestehsia for castration

Back 15

- commonly held in an upright position with the weight borne on the buttocks and the rear legs firmly flexed
- anesthetics not commonly used

Front 16

porcine restraint and anesthesia for castration

Back 16

- anesthesia not routinely used except for mature boars
- restraint up to weaning age: hold pig by its rear legs and cradles body between knees
- restraint for larger pigs: grab rear leg and pull backwards quickly to pull the pig off its feet then put one knee on neck and one behind front leg, holding both the upper legs, surgeon castrates pig with one knee on flank
- mature boars need restraint with lariat behind canines and anesthesia with sodium pentobarbital (intratesticular) or pentothal or surital (ear vein)

Front 17

definition: open castration

Back 17

- removal of testicle by incising the common vaginal tunic prior to removal of the testicle
- testicle is removed and common vaginal tunic is left in place or removed following removal of the testicle

Front 18

definition: closed castration

Back 18

- removal of testicle without incising the common vaginal tunic
- testicle is removed by dividing the entire spermatic cord including the common vaginal tunic, at the same time
- usual routine is to remove the testicle with an emasculator which crush cord
- prior to cutting the entire cord and common vaginal tunic a ligature is sometimes placed to close the opening into the peritoneal cavity

Front 19

open castration technique in standing equine

Back 19

- sedate, restrain, surgically prep testicles
- local anesthesia of scrotum and spermatic cord (line block on ventral aspect and into parenchyma of each testicle): easier than injecting into spermatic cord
- break through mesorchium between vas deferens and testicle (ligate vascular component if mature)
- emasculator
- surgical incision should provide adequate ventral drainage (can remove median septum of scrotum but usually not necessary)
- wait until hemorrhage has stopped before leaving premises or allowing animal to leave

Front 20

process of testicular blocks

Back 20

anesthetic is carried to the pampiniform plexus and the nerves which are in close proximity are blocked

Front 21

positioning of emasculator

Back 21

cutting edge of emasculator (nut side) placed distally: nut to nut
perpendicular to the long axis of the cord and cut without tension
- remove common vaginal tunic with emasculator

Front 22

castration technique in recumbent equine

Back 22

- essentially same as for standing castration
- Henderson castrating tool to clamp spermatic cord: clamp with jaws at right angle to long axis of tool attached to drill that twists cord until it breaks

Front 23

general comments on castration techniques with primary closure

Back 23

- not routine but greater recent use
- more time consuming and more expensive
- wound closed after surgery
- common on unilateral cryptorchid to remove testicle that isn't retained
- general anesthesia and aseptic technique required
- can consist in removal of only the testicle or removal of testicle plus a major part of the scrotum

Front 24

removal of only the testicle with primary closure

Back 24

- commonly on younger animals
- GA and normal surgery prep
- skin incision over spermatic cord anterior to scrotum
- incision into vaginal tunic
- testicle delivered through incision
- ligament of epididymis is divided
- vascular elements of spermatic cord are isolated, ligated and cut
- cremaster muscle and vas deferens cut to release testicle
- common vaginal tunic and SC tissue are closed with suture
- skin is closed with subcuticular pattern

Front 25

removal of the testicle plus a major portion of the scrotum with primary closure

Back 25

- commonly used on mature animals
- GA and normal surgery prep
- elliptical skin incision centered over the median raphe including skin of scrotum
- SC tissue divided along margins of incision and scrotum is removed
- vascular elements of spermatic cord are ligated and testicles are removed
- deep sutures to replace dead space and SC and skin layers are closed

Front 26

surgical technique for bovine castration

Back 26

- no GA or surgical prep
- testicle is accessed by either: removing the ventral 1/3 of the scrotum or vertical incisions over each testicle
- testicles are removed by traction with either: the common vaginal tunics intact, after incising the common vaginal tunics, an emasculator, scraping the spermatic cord or with a Henderson castration tool.

Front 27

bovine castration by removing the ventral one third of the scrotum

Back 27

- most common method in young animals
- accomplished by pulling downwards on the most ventral aspect of the scrotum and using a knife to make a horizontal incision through the skin and the median raphe
- surgical drainage not as adequate as with vertical incisions

Front 28

bovine castration by incising vertically over each testicle

Back 28

- most commonly done after pulling distally on the skin of the scrotum inserting knife just distal to lateral aspect of testicle forcing knife through median raphe to exit through other side and then forcing knife distally to produce anterior and posterior skin flaps
- Newberry castration tool commonly used to make these incisions
- more time consuming procedure used for steers destined for the show ring: better looking scrotum

Front 29

other bovine castration methods

Back 29

- Burdizzio emasculatome: blood less castration involving dividing the spermatic vessels without incising skin, takes 6 weeks for testicles to atrophy
- elastrator bands: testicles slough off due to interruption of blood supply (tetanus more common with this method)
- chemical castration with an irritant: only suggested for newborns, irritation injected directly into testicle, inflammatory reaction causes atrophy of testicle

Front 30

surgical technique for removal of ovine and caprine testicles

Back 30

- removal of the bottom one third of the scrotum to gain access
- traction to the testicle contained within the common vaginal tunics

Front 31

considerations with castrations of older goats

Back 31

- will sometimes go into shock if castrated using the same methods as used in cattle
- best to use sedation and local anesthetics
- consider ligation of the spermatic vessels

Front 32

other castration methods for ovine and caprine

Back 32

emusculatone and elastrator bands

Front 33

pre-castration checks in porcine

Back 33

check for inguinal hernias by having the handler apply pressure to the chest and abdomen when restraining the pig: increased abdominal pressure causes protrusion of intestines through the external inguinal ring

Front 34

surgical technique for porcine castration

Back 34

- skin incisions over each testicle: closed or open technique
- closed technique: testicle is free dfrom CT and remmoved by either grasping and pulling to break the supporting structures in the abdomen, scraping the cord till it divides or cutting the cord with side cutters (wire cutters)
- open technique: incision continue through common vaginal tunic, tunics are left

Front 35

surgical technique for mature boars

Back 35

- use GA
- use closed technique and cut the entire spermatic cord including the vaginal tunic with an emasculator

Front 36

castration post-op treatment and care

Back 36

- antibiotics: procaine penicillin G in horses
- tetanus prophylaxis: antitoxin and/or toxoid (just toxoid if previously received it) to horses (careful with Theiler's disease in older horses, avoid antitoxin), lambs and kids are given antitoxin at 1/10th dose in areas where tetanus is common
- horses should be given adequate exercise starting the day following castration, other species usually encouraged to exercise immediately following surgery
- check on animal frequently after surgery

Front 37

castration post-op complications

Back 37

- go over complications with owner prior to surgery!
- swelling and edema most common, associated with lack of ventral drainage (inadequate incision size); Tx: increase incision, NSAIDs, exercise
- infections, predisposed by ligatures and lack of drainage; Tx = drainage, removal of infected tissue, antibiotics, forced exercise
- hemorrhage: bleeding for more than 15 mins usually from testicular artery, caused by faulty emasculator or improper application
- eventration-herniation: omentum, intestine (i.p. Draft Horses, Stdbred, Tennessee Walking Horses)
- peritonitis (uncommon)
- damage to penis (unusual)
- hydrocele (unusual)
- tetanus
- failure to change obnoxious behaviour

Front 38

infections post-castration

Back 38

- Champignon (Streptococcus): associated with infected end of the spermatic cord and a large amount of granulation tissue
- Scirrhous cord (Staphylococcus): scrotal incision heals but chronic infection involving stump causes enlargement and eventually drainage
- occasionally the entire spermatic cord becomes infected and enlarged to the point that it can be palpated rectally
- clostridial infections are possible and are a serious problem

Front 39

management of post-castration hemorrhage

Back 39

- identify blood vessel and ligate, anesthetise if necessary
- if source cannot be identified pack scrotum with sterile gauze and suture to skin to hold in place for 24-48 h
- drugs to decrease fibrinolysis and/or decrease clotting time (not v. effective): aminocaproic acid, premarin
- refer if bleeding continues
- broad spectrum antibiotics prophylactically

Front 40

chars post-op herniation-eventration

Back 40

- rare but potentially fatal problem
- omentum can be ligated and removed if no intestine involvement
- herniations of intestine usually occur 4h post-op and up to 12 days later, usually secondary to straining from colic or casting
- previous hernias are risk factor

Front 41

prevention of post-castration herniation-eventration

Back 41

- closed castration + ligation of spermatic cord reduces the risk
- closure of the external inguinal ring at the time of castration is suggested in very high risk cases

Front 42

management post-castration herniation/eventration

Back 42

- protect bowel from contamination and damage and risk with sterile saline
- replace in scrotum and close with towel clamps prior to transport if possible or protect with moist towels
- broad spectrum antibiotics
- banamine for analgesia and anti-endotoxic props
- surgically replace bowel into abdomen and close external inguinal ring
- survival rates between 36 to 87%

Front 43

CS peritonitis

Back 43

- fever
- depression
- increased pulse rate
- colic
- dehydration
- diarrhea
- anorexia

Front 44

Dx tests for post-castration peritonitis

Back 44

abdominocentesis
- fluid submitted for cytology, bacterial culture and sensitivity testing
- can reach 100,000 cells/uL in horses without infectious peritonitis (rxn to blood)

Front 45

management of peritonitis

Back 45

- broad spectrum antibiotics and specific antibiotics following sensitivity results
- NSAIDs
- anti-endotoxemic medications: polymyxin B and hyperimmune serum
- indwelling drains in abdomen for abdominal lavage

Front 46

castration and penile damage

Back 46

- due to inept surgeon mistaking penis for testicle
- surgery to repair defects
- NSAIDs to reduce swelling and edema
- support penis if prolapsed and replace after decrease of swelling

Front 47

chars post-castration hydrocele

Back 47

- unsual complication
- accumulation of sterile fluid in the common vaginal tunic: more common in open castrations where tunic isn't removed
- more common in mules
- treatment only to correct appearance: remove distended common vaginal tunic

Front 48

horses retaining obnoxious behaviour post castration

Back 48

- learned behaviour in older stallions
- extra testicular source of testosterone: adrenal gland
- "proud cut" = all genetic tissue not been removed but is very unlikely and has no real effect

Front 49

synonyms of retained testicle

Back 49

- cryptorchid
- high flanker
- rig or ridgling
- original

Front 50

retained testicles in ruminants

Back 50

- very seldom have testicles retained in the abdomen
- if testicle not in scrotum it is usually subcutaneous relatively close to the external inguinal ring
- skin incision can be made directly over the testicle and the testicle can be removed using an emasculator

Front 51

retained testicles in swine

Back 51

- have retained abdominal testicles
- not economically sound to removed in pigs: meat quality not affected

Front 52

retained testicles in equine

Back 52

- testicles usually present in scrotum at birth
- impossible to differentiate between testicle and bulb of gubernaculum in foal by palpation (testicles were "pulled back" after being present)
- if colt still has retained testicle >2yrs, unlikely that it will find its way to the scrotum naturally
- horses with retained testicles considerably more difficult to manage than stallions (most common reason for presenting to surgery)

Front 53

heritability of retained testicles in equine

Back 53

- considered by many to be a heritable condition
- some breeds allow registration of foals sired by stallions
- considered unethical to surgically reposition a testicle in the scrotum

Front 54

Dx of retained testicle

Back 54

- palpation: deep inguinal, after relaxation of cremaster muscle or rectally
- ultrasound
- scars of previous surgery
- lab diagnostics: estrogen levels (>3 yrs & >400 pg/ml = testicular tissue, 100 = no tissue), testosterone levels (prior to and after injection of hcG, >7 nanomols/liter = testicle or in urine with gas chromatohraphy)
- location of testicle

Front 55

location of retained testicle

Back 55

- testicles are retained on the right and left with equal regularity
- left testicle is larger in fetus prior to descent
- size many times persists after descent
- right testicle if retained is often present in inguinal canal
- 75% of undescended left testicles and 42% of undescended right testicles are in abdomen

Front 56

inguinal approach for retained testicle

Back 56

- through the inguinal canal
- use if question about location

Front 57

parainguinal approach for retained testicle

Back 57

- 4-5 cm anterior and medial to the external inguinal ring
- easier to reconstruct the area

Front 58

ventral midline or paramedian approach for retained testicle

Back 58

- indicated for bilateral retention although both abdominally retained testicles can normally be removed through a single inguinal or parainguinal incision
- ventral midline approach complicated by penis and prepuce

Front 59

flank approach for retained testicles

Back 59

- may be performed on standing animal
- must be sure testicle is in abdomen
- follow mesorchium or vas deferens