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Basics ⬇

Outline

BASICS

Overview!!navigator!!

  • Common technique for the elective surgical removal of the testes in equids
  • Organ systems affected—reproductive

Signalment!!navigator!!

Intact male equids of any age.

Signs!!navigator!!

Normal testis size, shape, and consistency.

Causes and Risk Factors!!navigator!!

N/A

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Differential Diagnosis!!navigator!!

N/A

CBC/Biochemistry/Urinalysis!!navigator!!

Laboratory parameters should be normal prior to routine castration.

Other Laboratory Tests!!navigator!!

N/A

Imaging!!navigator!!

N/A

Other Diagnostic Procedures!!navigator!!

N/A

Pathologic Findings!!navigator!!

N/A

Treatment ⬆ ⬇

TREATMENT

  • The castration uses a closed technique under general anesthesia
  • The patient is placed in lateral recumbency with the upper rear limb pulled lateral/caudal to expose the testes
  • The patient is scrubbed and prepared for surgery as described for routine castration
  • The testes are exposed following a scrotal skin incision over each testis or by removing a 3 cm strip of the median raphe of the scrotum
  • The fascia is stripped away from the exteriorized testicle, exposing the spermatic cord as far proximal as possible
  • The Henderson instrument is inserted into a 14.4 V cordless hand drill with a 0.95 cm (0.375 inch) removable chuck
  • The drill is placed in a sterile shroud
  • The pliers of the instrument are placed on the spermatic cord just proximal to the testis
  • The drill is powered to rotate the instrument in a slow clockwise direction. Allow the tip of the instrument to be drawn into the incision, approximately 2 cm, as it starts to rotate. As the spermatic cord twists, do not allow the instrument to go any farther into the incision. The rotation can moderately be increased, as the cord starts to elongate just before it severs. Once the cord fatigues, more tension can be placed on the cord to complete its separation and removal of the testis. A tightly coiled cord is left behind, which achieves hemostasis
  • The instrument is removed and the operation is repeated on the other side. The incision site is inspected for bleeders. Excess fascia and/or fat is removed. The incision is left open and sprayed with a topical antiseptic/spray bandage. The horse is allowed to stand and is put into a stall to complete anesthetic recovery

Medications ⬆ ⬇

Outline

MEDICATIONS

Drug(s) of Choice!!navigator!!

Anesthesia

  • Preoperative sedation with xylazine (1.0–1.1 mg/kg IV)
  • Butorphanol (0.01–0.02 mg/kg IV) may be combined with xylazine to further sedation and analgesia
  • Induction with ketamine hydrochloride (2.2 mg/kg IV) combined with diazepam (0.03–0.06 mg/kg IV)
  • Anti-inflammatory therapy to help control swelling and pain postoperatively—phenylbutazone (2–4 mg/kg PO or IV) or flunixin meglumine (1 mg/kg) or ketoprofen (0.5 mg/kg)
  • Antibiotic therapy is not needed in a routine, uncomplicated castration
  • Tetanus toxoid prophylaxis

Contraindications/Possible Interactions!!navigator!!

N/A

Follow-up ⬆ ⬇

Outline

FOLLOW-UP

N/A

Patient Monitoring!!navigator!!

  • The patient should be confined to the stall until complete recovery from anesthesia
  • The surgical site should be monitored daily for hemorrhage, evisceration, excessive swelling, and/or infection
  • Forced exercise twice daily for a minimum of 20 min for the first 10–12 days to help reduce swelling and improve drainage
  • Cold water therapy for 15–20 min daily for 3–5 days

Prevention/Avoidance!!navigator!!

N/A

Possible Complications!!navigator!!

  • Hemorrhage—excessive hemorrhage may occur if too much tension is put on the spermatic cord before it fatigues and fractures
  • Treatment for excessive hemorrhage should include identification and ligation of blood vessels
  • Excessive preputial/scrotal swelling results from poor drainage from the scrotum:
    • Tranquilization, surgical scrub, and manually opening the surgical site will allow drainage
  • Excessive preputial/scrotal swelling may also result from infection. If infected—antibiotics, anti-inflammatory therapy, and drainage of the site are indicated
  • Evisceration of the abdominal contents is an uncommon occurrence, which can be fatal if not treated. The horse should be anesthetized, the intestinal contents cleaned, and viable intestine replaced. The superficial ring should be sutured closed
  • Some males may continue to display male-like behavior despite castration. This is a learned behavior and is not associated with testosterone production

Expected Course and Prognosis!!navigator!!

N/A

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Associated Conditions!!navigator!!

A simplified version of the technique, “Equitwister,” has been described.

Age-Related Factors!!navigator!!

N/A

Zoonotic Potential!!navigator!!

N/A

Pregnancy/Fertility/Breeding!!navigator!!

N/A

Internet Resources!!navigator!!

The Horse. The Equitwister: a simplified way to castrate working equids. http://www.thehorse.com/articles/37413/the-equitwister-a-simplified-way-to-castrate-working-equids

Suggested Reading ⬆ ⬇

Reilly MT, Cimetti LJ. How to use the Henderson castration instrument and minimize castration complications. Proceedings of the 51st American Association of Equine Practitioners (AAEP), Seattle (3–7 December 2005). Lexington, KY: AAEP, 2005.

Author(s) ⬆

Author: Ahmed Tibary

Consulting Editor: Carla L. Carleton