Contributors: Andrew Gardiner, Jill Sammarco

 Species: Canine   |   Classification: Techniques

Introduction Requirements Preparation Procedure Aftercare Outcomes Further Reading


  • Surgical removal of the testes via a prescrotal incision and 'open' castration technique.
    Print-off the owner factsheet on All about neutering All about neutering to give to your client.


  • Inhibition of male fertility and associated behavioral responses.
  • In the treatment of certain diseases influenced by male sex hormones, eg prostatic diseases Prostate disease , perianal adenomas Adenoma / adenocarcinoma and perineal hernias Perineum: rupture.
  • In the treatment of testicular Testicle: neoplasia , epididymal or scrotal neoplasia.
  • In the treatment of orchitis Orchitis / epididymitis.
  • In the treatment of congenital problems, eg abdominally retained testicles Testicle: cryptorchidism.
    In cryptorchid animals an inguinal and/or abdominal incision is likely to be required.
  • In the treatment of trauma to this region.
  • As part of the procedure of scrotal urethrostomy.
  • As part of the treatment of certain endocrine conditions and occasionally as part of the treatment to control idiopathic epilepsy Epilepsy: idiopathic.


  • 'Open' castration, when the testicular tunics are entered and reflected, allows the surgeon to place ligatures directly onto the vascular cord and ductus deferens, thereby minimizing the chance of ligature slippage or loosening.


  • An indirect opening into the peritoneal cavity is created; however under acceptable operating conditions, infection should not be a major issue.
  • Operating time is slightly longer.

Alternative Techniques

  • Periodic administration of anti-androgenic compounds may be a suitable alternative for some of the indications for castration.
  • Chemical sterilization by injection of zinc gluconate Zinc gluconate (for nonsurgical sterilization in the male dog) into testicle. Indicated for 3-10 month old dogs. Dose based on testicle width (Neutrosol® injectable solution).
  • An alternative perineal castration incision can be used when the technique is performed along with perineal hernioraphy to avoid respositioning the dog.
  • A closed castration technique Closed castration , whereby the the testicular tunics are not entered, may alternatively be performed.
  • Castration may be combined with scrotal ablation in certain situations.

Time Required


  • 15 min.


  • 20-30 min.


Materials Required

Minimum equipment

  • Standard surgical pack.

Minimum consumables

  • Absorbable suture material for ligation and intradermal sutures, eg polyglactin (Vicryl) 2/0, 3/0, 4/0.



  • Should include routine analgesia.

Dietary Preparation

  • Fast animal for 12 hours prior to anesthetic to prevent reflux esophagitis.

Site Preparation

  • On the ventral midline prescrotal area.
  • Routine surgical skin preparation.
    To avoid irritating the skin (and consequent self-trauma), the scrotum itself should not be clipped or scrubbed; it can be draped out of the surgical field.




Step 1 - Examine testes

  • Verify that both testes are present in the scrotum.

Core Procedure

Step 1 - Exteriorize the testicle

  • Incise skin and subcutaneous tissues on the prescrotal midline.
  • Advance one testicle towards the incision by pressure on the scrotum.

Step 2 -

  • Incise through spermatic fascia to reach the parietal vaginal tunic of the exposed testicle. Testicular parenchyma should not be exposed, ie the tunica albuginea should remain intact.
  • Fenestrate the spermatic fascia and place a clamp across the ligament of the tail of the epididymis.
  • Sharply divide the ligament and fascial attachments above the clamp and leave the clamp in situ temporarily for hemostasis (this structure rarely needs ligating).


  • The testicle can be exteriorized further at this stage.
  • Gently wipe the spermatic cord with a gauze sponge if necessary to retract fascial layers.
  • Double or triple clamp and then ligate the testicular artery and vein (together) and then the ductus deferens.
  • Place a second encircling ligature around both the vascular cord and ductus deferens.
  • Transect the cord above a hemostatic clamp.
  • Release the cord under control of thumb forceps, observe for hemorrhage and replace it within the tunic.
  • Advance the second testicle into the incision, incise the fascial layers, and repeat as above.


Step 1 - Closure

  • Dense fascial layer are apposed with interrupted or continuous sutures.
  • Subcutaneous tissues are closed with simple interrupted or continuous absorbable sutures.
  • Intradermal or subcuticular sutures can be placed instead of skin sutures, or else the skin can be closed in routine fashion.




  • Post-operative analgesia Analgesia: overview is required - best given as part of preanesthetic medication.

Antimicrobial therapy

  • Antibiotics should not be necessary for routine, elective castration.

Wound Protection

  • Some dogs may require an Elizabethan collar Elizabethan collar to prevent interference with skin sutures.

Potential complications

  • Hemorrhage from slipped or misplaced ligatures or undiagnosed bleeding disorders.
  • Scrotal hematoma from traumatic technique.
  • Infection/dehiscence if poor technique or operating standards.
  • Scrotal skin reaction if this area is clipped or scrubbed.


Follow up

  • Suture removal, if skin sutures used, in 7-10 days.



Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gourley J (1998) Early neutering of cats and dogs. Vet Rec 142 (9), 228 PubMed.
  • Michell A R (1998) Neutering and longevity in dogs. Vet Rec 142 (11), 288 PubMed.
  • Poole C (1998) Early neutering of cats and dogs. Vet Rec 142 (9), 227-228 PubMed.
  • Thornton P D (1998) Early neutering of cats and dogs. Vet Rec 142 (8), 200 PubMed.

Other sources of information