The Surgical Procedure to Neuter a Dog

Dog prepped for surgery

Kateryna Kukota / Getty Images


In this photo gallery, enter a veterinary surgical suite to see a dog neuter surgery performed, also known as a canine castration. There’s no need for you to gown up, throw on a pair of sterile gloves, and add a face mask, though. We’ll keep you away from the sterile field, while still allowing an up-close and personal look during a dog neuter.

During a canine castration, the dog is kept asleep and pain-free with a well-balanced anesthetic protocol and maintained on gas anesthesia. Many veterinarians also place an intravenous catheter to give IV fluids and apply monitoring equipment to evaluate a pet’s vital signs during the procedure. Monitoring equipment can record heart and respiratory rates, blood pressure, oxygen saturation levels, and electrocardiogram readings of the heart rhythm. Although a dog neuter is not as invasive a procedure as a canine spay, male dogs still receive ample pain medication before, during, and after surgery.

Now that you know this male pup will experience no pain or discomfort during his procedure, let’s scrub in and get ready to neuter a dog. 

  • 01 of 08

    Shaving and Scrubbing the Surgical Area

    Pre-op photo of a dog neuter surgery © Janet Tobiassen Crosby DVM
    Janet Tobiassen Crosby DVM

    After the dog is under anesthesia and hooked up to various monitoring equipment, surgical prep can begin. For a normal dog neuter, a single incision is made directly in front of the testicles and scrotum. Dogs with undescended testicles, a condition known as cryptorchidism, will experience a procedure more similar to a canine spay, in which the veterinarian will likely have to cut open the abdomen to find the testicles.

    Occasionally, a scrotal ablation may be performed during a dog neuter as well. Instead of removing only the testicles, the veterinarian will also remove the scrotum to prevent it from filling with blood after surgery. This surgery is usually performed on larger, older, more active dogs rather than small, young puppies.

    To keep things simple, this step-by-step photo gallery is of a routine dog neuter. Both testicles have descended into the scrotum, and the dog is fairly young and small, so a single incision will be all that is necessary. To ensure the surgical field is sterile, all the hair is clipped away from the future incision site. Ideally, two-inch margins are left around the entire incision site to ensure no hair creeps in.

    After the hair has been clipped and removed, a veterinary technician or assistant will scrub the surgical area with a disinfecting solution. Instead of scrubbing from side-to-side, the vet tech will scrub in a widening circle pattern, moving outward from the incision site. This prevents hair and dirt from being dragged back into the surgical area and ensures the incision site is as clean as possible.

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  • 02 of 08

    Incising the Skin

    Making the skin incision
    Janet Tobiassen Crosby DVM

    Once the surgical area is clipped, cleaned, and draped with sterile drapes, surgery can begin. The single incision is made in the skin, directly in front of the scrotum. Each testicle is pushed up and through the single incision, rather than making two separate incisions for each testicle. Scrotal incisions are avoided because the scrotal tissue is thin, sensitive, and bleeds more than a skin incision.

    There are two ways to do a dog neuter: open or closed.

    In an open castration, the vaginal tunic—the tough membranous covering of the testicle and associated structures—is incised, allowing easy visualization of the spermatic cord. If the vessels are particularly large, an open castration is preferred, since each structure is tied off (ligated) separately to prevent bleeding and slippage.

    In a closed castration, the tunic is not incised, and the spermatic cord and contained structures are ligated all at once, usually with two or three separate knots to prevent bleeding.

    This photo gallery demonstrates the closed castration method.

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  • 03 of 08

    Exteriorizing the Testicles

    The testicle is exteriorized
    Janet Tobiassen Crosby DVM

    After the skin is incised, the veterinarian teases a testicle through the incision. In this closed castration method, the veterinarian clamps the entire structure at once—the vas deferens (spermatic cord), pampiniform plexus (vessels around the vas deferens), cremaster muscle, and arterial supply. By clamping all the vessels and structures, the veterinarian prevents them from slipping back into the body after the testicle is removed, and it also prevents hemorrhage.

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  • 04 of 08

    Ligating the Vessels

    Transfixing suture is tied
    Janet Tobiassen Crosby DVM

    To prevent bleeding, the veterinarian ligates the vessels with a dissolvable suture. There is always some danger that the vessels may slip out of a knot. Transfixing ligatures help to ensure things stay where they should, and no bleeding occurs. After the first testicle has been removed and the vessels ligated, the procedure is repeated on the second testicle.

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  • 05 of 08

    Closing the Incision

    Closing the incision
    Janet Tobiassen Crosby DVM

    Once both testicles are removed and the vessels ligated, the veterinarian checks for bleeding or seepage before closing the skin. If everything looks good, the skin is closed using the same dissolvable suture that was used to ligate the testicles.

    Ideally, the incision is small, and is closed in multiple steps. Internal skin sutures are placed to close the subcutaneous tissue, while a second layer is sutured under the skin, bringing the skin edges together. If internal sutures are used, some veterinarians may apply tissue glue to the incision for a third level of closure. Many veterinarians opt for this closure technique to avoid prickly stitches on the outside skin surface, which may prompt dogs to lick and chew. Some veterinarians will still close the incision with skin sutures, which will need to be removed in 10 to 14 days. 

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  • 06 of 08

    Checking the Surgical Incision

    Neuter surgery is completed
    Janet Tobiassen Crosby DVM

    The incision in this small dog is less than one inch long. With such a small incision, there is usually minimal hemorrhage and swelling. After closing the incision, the veterinarian inspects the site to ensure the skin is closed properly and there is no bleeding.

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  • 07 of 08

    Applying Tissue Glue

    Applying the surgical glue to close the incision © Janet Tobiassen Crosby DVM
    Janet Tobiassen Crosby DVM

    Tissue glue helps seal the edges of the skin together without using itchy skin sutures. A thin layer of tissue glue also prevents minor seepage from the incision.

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  • 08 of 08

    Recovering from Anesthesia

    Ready to wake up
    Janet Tobiassen Crosby DVM

    After the incision site is checked and cleaned up, the dog is ready to be recovered from anesthesia. Pets are closely monitored during the recovery phase to ensure a smooth recovery to prevent injury upon waking. 

    Once the dog returns home to his owner’s care, they have the challenging task of keeping him quiet and calm, and also preventing him from licking or chewing at the incision site. If a dog is too active after surgery, the scrotum can fill with blood, which may require additional surgery. Licking and chewing can also be problematic, especially if the incision site becomes infected or reopens.

    Fortunately for this dog, he is young and small, with a tiny incision, so he should heal quickly with no problems. But, if your dog has recently been neutered and has been too active or is licking at his incision, contact your veterinarian for help.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.