HOW-TO SESSION:
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How I Manage Castration Complications in
the Field
P.O. Eric Mueller, DVM, PhD, DACVS
Minimizing the incidence of postoperative complications associated with equine castration should be
the primary goal of the practitioner. Proper case selection, knowledge of pertinent clinical anatomy,
perioperative physical examination, and correct surgical technique will minimize the incidence of
complications. When complications do occur, early recognition and treatment will maximize the
chance of a successful outcome. Author’s address: University of Georgia, College of Veterinary
Medicine, Athens, GA 30602-7385; e-mail: [email protected]. © 2015 AAEP.
1.
Introduction
Castration is one of the most common elective surgical procedures performed in the field. The procedure is most often performed to abate unwanted
aggressive, masculine behavior in horses not intended for breeding. Although the procedure is
considered routine, various postoperative complications including excessive swelling and edema,
hemorrhage, infection, omental herniation, eventration, hydrocele, or septic peritonitis may occur.1–3 In one recent retrospective study, 10% of
equids undergoing routine, elective castration experienced complications related to the procedure.1
Seventy-six percent of these complications were
classified as mild and did not require emergency
treatment.1 Although the vast majority of horses
that experience complications are successfully
treated on the farm with no long-term adverse
effects, the increased morbidity and cost associated with additional veterinary care for a procedure that is perceived as “routine” often results in
additional concern of the practitioner and client
dissatisfaction.
For any surgical procedure, it is more desirable to
minimize the occurrence of postoperative complications rather than to have to deal with the associated
morbidity, time, and effort in treating them. A
thorough understanding of pertinent clinical anatomy,
strict attention to asepsis and surgical technique, and
proper postoperative exercise recommendations will
minimize the incidence of complications associated
with castration.3,4 However, when complications do
arise, the practitioner must be able to quickly recognize and correctly and aggressively treat them to
assure a rapid and successful outcome. Although a
comprehensive discussion of pertinent equine male
anatomy is beyond the scope of this presentation,
the principals of proper surgical technique, perioperative care and recognizing and treating common
complications associated with equine castration will
be discussed.
2.
Materials and Methods
Perioperative Evaluation
A complete history should be obtained including a
query of any medical conditions that may predispose
NOTES
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to complications such as congenital inguinal hernia,
cryptorchidism, or previous unsuccessful attempts
of general anesthesia or castration. A thorough
physical examination including palpation of both
testes and superficial inguinal rings should also be
performed. Absence of one or both descended testes, a history of congenital inguinal hernia, or abnormal swelling or enlargement of the inguinal ring
area should alert the practitioner to an increased
risk of postoperative complications at which time
they should strongly consider referral to a surgery
facility. Horses should be current on tetanus prophylaxis, with perioperative antimicrobial therapy
and perioperative analgesic therapy at the discretion of the practitioner. One retrospective study
performed in the United Kingdom reported 45% of
practitioners did not administer perioperative analgesics, with 18% administering them occasionally,
and 37% administering them routinely.5 The author routinely administers a single preoperative
dose of procaine penicillin (22,000 IU/kg, IM, once)
and perioperative phenylbutazone (4.4 mg/kg, once,
IV preoperatively, followed by 2.2 mg/kg, every 12 h,
for 3– 4 d).
Surgical Technique and Postoperative Care
Castration may be performed in the standing horse,
with the addition of incisional and intra-testicular
lidocaine administration, or under IV general anesthesia. The complication rate between these two
approaches is not significantly different.4,6 The approach utilized is dependent on practitioner preference, and the size and disposition of the horse.
From the initial scrotal incision to the final
stretching of the surgical incision to allow adequate
drainage, meticulous attention to asepsis and surgical technique will help minimize many of the complications that can be associated with routine
castration. When making the scrotal incision both
testes should be pushed firmly into the scrotum,
tensing the skin, tunica dartos, and scrotal fascia
tightly over the testis (Fig. 1). This will minimize
incorporating multiple tissue planes in the incision
and the chance of excessive subcutaneous tissue or
scrotal fascia becoming edematous and protruding
beyond the skin edges during early healing. Each
scrotal skin incision should be made approximately
1 cm from the median raphe, along the most dependent aspect of the scrotum, and extend from pole to
pole of each testis. This will allow easy exteriorization of the testis and minimize the amount of manipulation necessary to separate the scrotal fascia
from the underlying parietal tunic in preparation of
application of the emasculators. In addition, long
incisions allow for adequate drainage and prevent
premature healing of the skin incisions that can
result in accumulation of contaminated debris and
localized infection.
A variety of emasculators may be used to perform
equine castration. The author prefers the Serra
emasculators because of their vertically oriented
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Fig. 1. Photograph demonstrating tensing the scrotal skin over
the testes in preparation for the initial skin incision. This will
minimize incorporating multiple tissue planes in the incision and
the chance of excessive subcutaneous tissue or scrotal fascia
protruding beyond the skin edges and becoming edematous during early healing.
serrated crushing surface that provide excellent hemostasis and long handles to provide adequate leverage for emasculating larger-diameter spermatic
cords of older stallions. Correct application of the
emasculators is essential to provide adequate hemostasis. The emasculator is assembled to provide
crushing of the cord vasculature proximally while
simultaneously transecting the cord, distal to the
crush site. Four simple principals of emasculator
application: 1) nut-to-nut, 2) applying the emasculator perpendicular to the cord, 3) minimal tension,
and 4) leaving the emasculators on for 2–3 minutes
will minimize complications associated with postoperative hemorrhage. Regardless of the type of
emasculator, when correctly assembled, the prominent external assembly nut on the crushing apparatus should be positioned adjacent to the testis to be
removed (nut-to-nut) (Fig. 2). This assures that
crushing of the cord occurs proximal to the transection site. If the emasculators are applied
in the reverse orientation, the crush site would be
distal to the transected cord, and profuse hemorrhage would ensue. The emasculators should be
oriented perpendicular (90°) to the cord to prevent
premature cutting of the testicular artery before it is
fully engaged by the crushing apparatus. Minimal
tension refers to the tension of the spermatic cord
during emasculation. The emasculators should be
placed, closed just enough to engage and secure the
cord, then the emasculator and cord relaxed toward
the inguinal area (proximally), ensuring no skin is
incorporated in the emasculation, before fully closing the emasculator. This prevents the elastic testicular artery from recoiling proximally beyond the
grasps of the emasculator during incomplete or slow
application of the emasculator. Leaving the emas-
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Fig. 2. Photograph demonstrating proper application of the
emasculator with the prominent external assembly nuts facing
the testis and the correct perpendicular orientation to the spermatic cord.
Fig. 3. Photograph demonstrating stretching of the scrotal skin
incisions to promote adequate drainage. The skin should be
stretched until a small, but noticeable release in skin tension is
felt.
culators in place for 2–3 minutes is sufficient for
most horses to provide adequate hemostasis. In
older stallions or donkeys, the author will leave the
emasculators in place for 4 –5 minutes, or transfix
the cord with 2– 0 polyglecaprone 25a before emasculation. In addition, donkeys are reported to have
relatively large testicular vessels;7 therefore, the author routinely ligates the cord proximal to the emasculation site with a single absorbable transfixation
suture.
Following emasculation, the parietal tunic of the
spermatic cord should be grasped with Ochsner forceps before releasing the emasculator. Care should
be taken not to clamp across the entire width of the
cord, because this would preclude being able to identify a bleeder should it be present. The emasculator is released, the cord gently replaced into the
scrotal incision to relieve any remaining tension on
the cord, and the end of the stump examined. If no
bleeding is evident, it can be released. The end of
the transected cord should not be blotted or manipulated because this could disturb the existing clot
and predispose to hemorrhage.
After both testes are removed, the scrotal incisions should be examined for any excessive or pulsatile hemorrhage. If excessive hemorrhage is
identified, it may be clamped with a Carmalt forceps
or ligated (see hemorrhage). The scrotal skin incisions should be manually stretched with two fingers
until a sudden but small release in skin tension can
be felt (Fig. 3). This will allow for maximal drainage and prevent premature healing of the incisions.
Care should be taken to stretch only the skin, and
not the underlying subcutaneous tissues or vasculature that could result in inadvertent tearing of one
of the branches of the external pudendal vein.
Postoperatively, the author prefers to keep the
horse confined to a stall or small paddock for 24
hours for close observation for hemorrhage, prolapse
of subcutaneous tissue, omentum, or intestine, and
maturation of the clots on the testicular artery.
After this 24-hour period, the horse should be actively exercised (lunge or trot) for 5 to 7 days to
promote drainage, prevent premature closing of the
incision sites, and minimize scrotal swelling.
3.
Results
When complications do occur it is important that the
client or veterinarian recognize them early, and that
they are treated promptly and correctly to minimize
prolonged morbidity and client dissatisfaction.
Edema/Swelling
Some degree of postoperative swelling and edema is
expected after routine castration; being most evident 3 to 4 days after surgery with complete resolution in 12 to 14 days. More severe swelling that
results in clinical signs such as a stiff gait, reluctance to ambulate, or abnormal urination is considered abnormal and should be evaluated. Excessive
scrotal swelling is usually due to the scrotal incisions being too small or not being stretched adequately after surgery, or noncompliance of the
owner related to active postoperative exercise recommendations. This can result in premature closure of the incisions and accumulation of serous
fluid in the scrotum. Excessive swelling may also
be a sign of a localized infection or abscess (see
infection). Excessive noninfectious swelling is
most easily treated on the farm by sedating the
horse, aseptic preparation of the scrotal area, manually opening and stretching the scrotal incisions
with sterile gloved hands to facilitate drainage, and
a 3–5-day course of nonsteroidal anti-inflammatory
drugs (NSAIDs). The owner should follow this up
with cold-water hydrotherapy and active exercise or
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Fig. 4. Photograph demonstrating arterial hemorrhage from the
scrotum following improper application of the emasculator during
castration.
lunging twice daily to promote drainage and prevent
premature wound closure.8
Hemorrhage
It is not unusual to have several drops of blood or a
slow drip of blood associated with a castration for 5
to 10 minutes after the procedure. This is especially true if the median raphe has been excised or
the bottom third of the scrotum has been removed to
facilitate drainage. The source of this blood is often
small, subcutaneous vessels. However, hemorrhage in the form of a fast drip or pulsatile stream,
or of any kind that persists for more than 15 minutes
after the procedure is completed is considered abnormal and should be addressed.2,4 Although the
testicular artery is the most common source of significant hemorrhage, superficial branches of the external pudendal vessels and the cremaster artery
may also be a source. Significant hemorrhage most
often occurs because of improper application of the
emasculator (Fig. 4). Initial treatment is aimed at
identifying and stopping the source of hemorrhage.
If the horse is still anesthetized, anesthesia should
be prolonged with additional anesthetic and the
distal aspect of the spermatic cord isolated with a
sterile gloved hand or curved Carmalt clamp. Ex212
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ternally directed tension on the transected stump
during manipulation may be sufficient to significantly slow or stop the hemorrhage associated with
the testicular or cremaster artery. Therefore, the
stump should be closely examined under minimal
tension before correctly concluding it is not the
source of hemorrhage. If the distal stump is identified to be the source of hemorrhage, it may either
be re-emasculated, or more commonly ligated with a
transfixation suture of 1-0 or 0-0 absorbable suture.a
If the stump has retracted too far proximally into
the inguinal canal and cannot be exteriorized for
ligation or emasculation, or the horse has already
recovered from anesthesia, a large, curved crushing
forcep(s) (Carmalt) may be used to isolate and secure the distal end of the stump. The horse is then
recovered with the clamp(s) in place and maintained
in a stall for 24 to 48 hours for close observation,
after which time the clamps can be removed with the
horse standing. In the standing horse, the author
prefers to identify and secure the source of hemorrhage with curved Carmalt forceps rather than dealing with the frustration of trying to isolate and
ligate the specific source of hemorrhage.
If the source of hemorrhage cannot be identified,
the scrotum should be packed with a 5–7-meter-long
piece of continuous sterile gauze (crypt packing),
sutured closed, and transported to the nearest referral facility. Referral is also strongly encouraged in
cases where considerable external blood loss has occurred or internal hemorrhage is suspected. Clinical
signs associated with significant blood loss and hypovolemic shock include tachycardia, tachypnea,
pale mucous membranes with an increased capillary
refill time, weak pulses, cold extremities, and sometimes colic. Intra-abdominal hemorrhage may be
confirmed in the field by trans-abdominal ultrasonography (swirling free peritoneal fluid) or an abdominocentesis. Monitoring pack cell volume and
total solids will not reflect the severity of acute blood
loss because of fluid distribution across intravascular and extravascular fluid spaces and hypovolemia
induced-splenic contraction. Changes in pack cell
volume and total protein (TP) may not be evident for
6 hours and 12 to 24 hours, respectively.2 Before
transport, the practitioner should consult the personnel at the referral facility for recommendations
on initiating intravenous fluid and broad-spectrum
antimicrobial therapy, as well as additional considerations necessary to stabilize the horse sufficiently
for shipping.
Infection
In a recent report, infection or abscess formation at
the surgical site occurred in 2% of equids undergoing
routine castration, with clinical signs developing
from 3–21 days after surgery.1 Local infection
most often results from premature closure of the
surgical incisions secondary to the incision being too
small or not being in the most dependent part of the
scrotum, or insufficient postoperative exercise.
HOW-TO SESSION:
The most common organism associated with these
infections is Streptococcus zooepidemicus; however,
other organisms may be involved. It is always recommended to obtain a culture and sensitivity to
direct appropriate antimicrobial therapy. Clinical
signs associated with localized incisional site infection include fever, swelling ⫾ purulent discharge,
lameness, or reluctance to ambulate. Treatment is
focused on opening the scrotal incisions sufficiently
to establishing ventral drainage and irrigation of the
site with sterile, balanced, isotonic fluids. This can
be accomplished on the farm with the horse standing
and sedated with xylazine (0.2– 0.4 mg/kg, IV) or
detomidine (0.005–.01 mg/kg, IV) and butorphanol
tarate (.01– 0.02 mg/kg IV). Broad-spectrum antimicrobial therapy is initiated until results of the
culture and sensitivity are available. Nonsteroidal
anti-inflammatory drugs are administered for analgesia and to promote ambulation. The owner
should actively lunge the horse twice daily until
there is complete resolution of clinical signs. For
the majority of horses, the above protocol should
result in resolution of clinical signs in 7 to 10 days.
More chronic or systemic infections usually require referral. Chronic Streptococcus sp. infection
of the cord (Champignon) becomes clinically evident
weeks to months after surgery. These horses usually present with a history of fever, a granulating
inguinal wound with purulent drainage, and a thickened spermatic cord remnant. Historically these
infections have been associated with ligation of the
spermatic cord with nonsterile suture materials.
However, with the use of commonly available sterile
absorbable suture materials and proper aseptic
technique, ligation of the spermatic cord does not
seem to be associated with an increased risk of infection.9 In these cases, infection is more established in the tissues and usually requires surgical
exploration of the area under general anesthesia
and resection of the residual infected cord deep in
the external inguinal canal.
Long-standing chronic diffuse infection of the
spermatic cord with Staphylococcus sp is known as a
Scirrhous cord. In these horses, the scrotal incision
heals normally and the infection extends proximally
along the spermatic cord remnant. Clinical signs
may not be apparent for months to years after castration, and are dependent on the extent of infection.
Horses usually present with fever and diffuse, firm,
inguinal swelling ⫾ single or multiple draining
tracts (Fig. 5). These infections may ascend beyond
the level of the internal inguinal ring and involve
the peritoneal cavity, being palpable per rectum as a
firm, thickened swelling associated with the internal
inguinal ring. Horses with peritoneal involvement
may develop septic peritonitis secondary to the primary disease or subsequent to surgical treatment.
Treatment involves en bloc resection of the affected spermatic cord and associated infected tissues to the most proximal extent of the infection,
establishing ventral drainage, long-term intravenous
FIELD SURGERY
Fig. 5. Photograph demonstrating chronic infection of the spermatic cord resulting in a Scirrhous cord. Notice the diffuse
thickening of the spermatic cord remnant associated with the
inguinal area.
broad-spectrum antimicrobials, and NSAIDs. Horses
with infection that extends beyond the internal inguinal ring have a guarded prognosis because of poor
surgical access and the high probability of the septic
peritonitis resulting in a severe systemic inflammatory response.
Omentum Eventration (Prolapse)
Eventration of inguinal or abdominal omental or
inquinal fat following castration is a rare and less
serious complication that, if it occurs, is usually
evident within the first 24 hours after castration.
Acute prolapse (Fig. 6) can be quite extensive and
alarming to the owner, whereas more chronic prolapse usually presents as cold, thickened, edematous
tissue protruding beyond the skin margins (Fig. 7).
Affected horses demonstrate no additional clinical
signs except for the prolapsed tissue, in contrast
with horses with intestinal eventration, which demonstrate signs consistent with moderate to severe
acute abdominal pain. A thorough physical examination of the patient and tissue is necessary to
assure that no important anatomical structures (intestine) are contained within the tissue. Manual
removal by external traction should not be attempted because of the risk of enlarging the internal
inguinal ring and predisposing to intestinal eventration. Rather, the horse is sedated, the tissue is
aseptically prepared, ligated with absorbable suture, and transected or emasculated distal to the
ligation suture and deep to the level of the skin
margin. Antimicrobials and NSAIDs may be administered but are generally not necessary.
Hydrocele
Hydrocele is an accumulation of serous or peritoneal
fluid contained within the remaining closed vaginal
tunic. Horses present with a flocculent, nonpainful
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Treatment is not necessary unless the owner finds
the swelling aesthetically displeasing. In these
cases the redundant tissue should be removed en
bloc under general anesthesia. Fluid aspiration
with a sterile needle should not be attempted because of the risk of causing a secondary infection
and inevitable likelihood of recurrence.
4. Complications in Which Referral Is Highly
Encouraged
Intestinal Eventration
Fig. 6. Photograph demonstrating an acute (⬍ 12 h) omental
prolapse. This was the only abnormal finding upon complete
physical exam.
swelling of the scrotal area. It is a rare complication that may become evident months to years after
castration. It seems to occur more commonly after
open (with respect to the vaginal tunic) castration.
Fig. 7. Photograph demonstrating omental prolapse of 4 days’
duration. The tissue is cold, edematous, and thickened.
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Eventration of intestine is a rare but serious complication of equine castration, occurring in 0.3 to
4.6% of castrations, with Standardbred, draft
breeds, and horses having had a congenital inguinal
hernia at an increased risk. Herniation usually occurs within the first 4 to 12 hours after castration
but has been reported to occur as late as 12 days
after castration.10,11 There does not seem to be a
significant difference in risk of eventration between
open and closed castration techniques.12 Partial or
complete inguinal/scrotal herniation should be suspected in any horse that demonstrates signs of acute
abdominal pain within 12 hours after castration.
Ligation of the spermatic cord with a transfixation
suture has been shown to reduce, but not completely
prevent, the risk of eventration.9 Horses deemed to
be at increased risk of intestinal eventration should
be referred for castration and primary closure of
external inguinal rings. If a small section of intestine herniates through the inguinal ring during surgery, the intestinal segment should be thoroughly
lavaged with sterile, balanced, isotonic solution, and
replaced into the abdomen. A second surgical approach directly over the effected inguinal ring will
be necessary to replace the intestinal segment and
close the external inguinal ring (slit) in the aponeurosis of the external abdominal oblique muscle.
The external inguinal ring should be closed with No.
2 absorbable suture material.b These horses should
be administered intravenous broad-spectrum antimicrobials and NSAIDs, and confined to a stall for 7
to 10 days for close observation. They may be hand
walked after 48 hours.
If intestinal eventration is evident after the horse
recovers from anesthesia or a significant length of
intestine has protruded through the inguinal ring
(Fig. 8), the immediate objective should be to protect
and preserve the exposed intestine and prevent further eventration of the intestine. The principals of
“clean, replace, and retain” the intestinal segment
should be employed by the practitioner in preparation for transport to a referral facility. The exposed
intestine should be thoroughly lavaged with sterile,
balanced, isotonic solution. If the segment is small
enough to be contained within the scrotum, it may
be replaced in the scrotum and the scrotal skin apposed with suture or several towel forceps. For
larger lengths of exposed intestine, a moist bed
sheet or large towel maybe used as a sling to support
HOW-TO SESSION:
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Iatrogenic Penile Damage
Fig. 8. Photograph demonstrating eventration of intestine 6 h
after routine castration. Photo courtesy of Dr. Steffan Witte.
Iatrogenic penile damage has been reported and
usually occurs when an inexperienced surgeon mistakes the shaft of the penis for the testis. This
should be completely avoidable with a thorough understanding of the pertinent clinical anatomy and sufficient surgical experience of the practitioner. As
with any surgical procedure, meticulous, atraumatic
handling of the tissue with minimal unnecessary tissue manipulation will minimize postoperative morbidity. Excessive manipulation and dissection of the
surrounding tissue may result in excessive inflammation, swelling, and paraphimosis. This is treated
with aggressive hydrotherapy, NSAIDs, and mechanical support of the penis until the inflammation subsides. If inadvertent direct penile damage (laceration
or transection) does occur, the horse should be transported to a referral facility for further evaluation and
treatment.
5.
the intestine during transport. These horses
should be administered intravenous broad-spectrum
antimicrobials and flunixin meglumine, and immediately transported to the nearest referral facility
for general anesthesia and ventral midline exploratory celiotomy. The prognosis is dependent on the
amount of intestinal compromise, degree of peritoneal contamination, and overall systemic condition
of the horse at admission, with reported survival
rates from 36 to 87%.2
Septic Peritonitis
Septic peritonitis is a rare but serious complication
of castration. Clinical signs associated with septic
peritonitis include fever, depression, anorexia,
tachycardia, tachypnea, colic, and diarrhea. Because the common vaginal tunic surrounding the
testes is an extension of the parietal and visceral
peritoneum and directly communicates with the
peritoneal cavity, a transient nonseptic peritonitis is
commonly associated with uncomplicated castration. Blood contamination during the procedure is
believed to elicit the inflammatory response. Intraperitoneal nucleated cell counts of greater than
100,000 cells/␮L have been reported for 5 to 7 days
after normal castration.13 Nucleated cell counts
and peritoneal protein concentration are not helpful
in differentiating between nonseptic and septic
peritonitis in the early postoperative period
(⬍ 5–7 d). Therefore, cytological evaluation for
the presence of degenerative neutrophils and intracellular bacteria as well as bacterial culture of
the peritoneal fluid should be performed to confirm the diagnosis. Horses with septic peritonitis
should be immediately referred for treatment with
intravenous broad-spectrum antimicrobials and
supportive therapy including intravenous fluids,
anti-endotoxemia therapy, and in advanced cases,
standing intraperitoneal lavage.
Discussion
Castration is one of the most common elective surgical procedures performed in the field. Although
the procedure is considered routine, various postoperative complications including excessive swelling
and edema, hemorrhage, infection, omental herniation, eventration, hydrocele, or septic peritonitis may
occur. It is more desirable to minimize the occurrence of postoperative complications rather than to
have to deal with the associated morbidity, time, and
effort in treating them. A thorough understanding of
pertinent clinical anatomy, strict attention to asepsis
and surgical technique, and proper postoperative exercise recommendations will minimize the incidence of
complications associated with castration. However,
when complications do arise, the practitioner should
be able to quickly recognize and correctly and aggressively treat them to assure a rapid and successful
outcome.
Acknowledgments
Declaration of Ethics
The Author declares that he has adhered to the Principles of Veterinary Medical Ethics of the AVMA.
Conflict of Interest
The Author declares no conflicts of interest.
References and Footnotes
1. Kilcoyne I, Watson JL, Kass PH, et al. Incidence, management, and outcome of complications of castration in equids:
324 cases (1998 –2008). J Am Vet Med Assoc 2013;242:820 –
825.
2. Getman LM, White NI. Review of castration complications:
Strategies for treatment in the field, in Proceedings. Am
Assoc Equine Pract 2009;55:374 –378.
3. Kilcoyne I. Equine castration: A review of techniques,
complications and their management. Equine Vet Educ
2013;25:476 – 482.
4. Schumacher J. Testis. In: Auer JA, Stick JA, eds. Equine
Surgery. 4th ed. Philadelphia: Elsevier, 2012:804 – 836.
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5. Price J, Eager RA, Welsh EM, et al. Current practice relating
to equine castration in the UK. Res Vet Sci 2005;78:277–280.
6. Portier KG, Jaillardon L, Leece EA, et al. Castration of
horses under total intravenous anaesthesia: Analgesic effects of lidocaine. Vet Anaesth Anal 2009;36:173–179.
7. Sprayson T, Thiemann A. Clinical approach to castration in
the donkey. In Practice 2007;29:526 –531.
8. Turner RM, Dobbie T. Stallion Reproductive Emergencies.
In: Orsini JA, Divers TJ, eds. Equine Emergencies: Treatment and Procedures. 4th ed. St. Louis, MO: Elsevier,
2014:432– 433.
9. Carmalt JL, Shoemaker RW, Wilson DG. Evaluation of
common vaginal tunic ligation during field castration in
draught colts. Equine Vet J 2008;40:597–598.
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10. Hunt RJ. Management of complications associated with
equine castration. Compend Contin Educ Pract Vet 1991;13:
1835–1843.
11. Boussauw B. Inguinal herniation 12 days after a unilateral
castration with primary wound closure. Equine Vet Educ
1996;8:248 –250.
12. Shoemaker R, Bailey J, Janzen E, et al. Routine castration
in 568 draught colts: Incidence of evisceration and omental
herniation. Equine Vet J 2004;36:336 –340.
13. Schumacher J. Complications of castration. Equine Vet
Educ 1996;8:254 –259.
a
Monocryl, Ethicon, Somerville, NJ 08876.
Vicryl or PDS, Ethicon, Somerville, NJ 08876.
b