neutered dogsNeutering is one of the most common surgical procedures in veterinary practice, but people often have very little understanding of what actually happens. This may be due to embarrassment, but it has led to some misconceptions and misunderstandings. In this blog, we’re going to look at what happens when your dog or male puppy comes in to “be done”.

Why do we neuter dogs?

Neutering male dogs has a number of beneficial effects; firstly, it irreversibly removes fertility, so you don’t need to worry about unexpected litters! It also reduces testosterone levels, reducing roaming and sexual behaviour; and removes the risk of testicular tumours and most prostate disorders.

What’s the proper name for the procedure?

In male dogs the operation is called castration. It involves surgical removal of both testicles. It is not the same as a vasectomy (where the testicles are left intact and in situ, but the tubes that carry sperm from them are cut).

When are dogs normally castrated?

The average is at about six months of age, although for giant breed dogs we often wait a bit longer as they mature later..

However, it is perfectly possible to castrate a much older dog, and this is regularly done to manage prostatic diseases. It is important to remember that castrating an adult dog is less likely to affect his behaviour than operating on a dog who is still in the “teenage” phase.

What preparation is required?

For obvious reasons, your dog will need a general anaesthetic to be castrated. Therefore, your dog will need to be starved overnight; otherwise, however, no special preparation is required. When you drop them in to us in the morning, we’ll go through a consent form with you – this is the time to tell us about any medical problems, or any concerns you may have. Our nurses will now admit your dog for the day. We do offer pre-operative blood tests to check kidney and liver function, but it’s not usually necessary for young dogs.

What happens after admission?

We’ll take your dog into the practice and off you go – but here’s your chance to find out what happens “behind the scenes”! Before we can perform surgery, we’ll weigh him (the anaesthetic drug doses are worked out by body weight) and give him a “pre-med” injection. This contains a mild sedative and a painkiller (pain relief is most effective when given before surgery). He’ll then be taken to a kennel to rest while the drugs take effect.

Induction and prep

When we’re ready for him (usually about half an hour after the pre-med), we’ll bring him into our preparation room. He’ll probably be a bit sleepy by now, but definitely still awake. Here we’ll clip a small patch of fur from a front leg, and one of the nurses will hug him while the vet injects a fast-acting, short-lasting anaesthetic into the vein. Once asleep, we’ll put a breathing tube down his throat to help him breathe, and will connect him to the anaesthetic machine which will provide him with oxygen and anaesthetic gas to keep him under.

The vet will now start to scrub up (so they’re sterile and won’t introduce any infection) while the nurse rolls your dog onto his back, clips the fur and prepares the surgical site with a skin disinfectant. The operating site in dogs is a patch of skin between the scrotum and the penis – we don’t open the scrotum up directly. Once the site is prepared, your dog is wheeled into the operating theatre, ties are used to hold his back legs wide apart, and sterile drapes are laid across his middle.

The operation

Castration is one of the quickest and simplest surgical procedures there is! The vet will gently squeeze your dog’s scrotum, pushing the testicle forwards, towards his penis. When the skin is tight, a scalpel blade is used to cut through it, so the testicle pops out, still covered in its membranous sac. A clamp is applied to the spermatic cord below the testicle, and dissolvable sutures tied around it to prevent bleeding. Then his testicle is simply cut off with the scalpel. The other one is removed the same way (ideally through the same hole), and the skin incision closed with two or three skin stitches, or more commonly dissolvable stitches in the skin.

After both testicles have been removed, and while the vet is stitching up, the painful part of the operation is over, so the anaesthetic is lightened, ready for him to wake up once the skin stitches are complete. He’ll then be moved to a recovery area.


The modern anaesthetic gases wear off very fast, and we’ll often be able remove the breathing tube within a few minutes. Most dogs are wide awake again within half an hour or so; at this point, we will usually have to put an Elizabethan Collar (or cone) on to stop him from licking and introducing infection. Almost always, he’ll go home the same day!


You dog mustn’t be allowed to lick the site or he will introduce infection which will delay healing. It is important that he wears his collar at all times. We will see him back to check the wound 1-3 days and 10 days after the surgery.

It’s important to remember that the scrotal skin is not removed, so it’s perfectly normal for an empty flap of skin to be present after surgery. Sometimes, this becomes a little swollen with fluid.

Some dogs can be sore after surgery, if this is the case we can put up additional painkillers for him for a few days.

However, most dogs are completely back to normal within a couple of days, except for an empty pouch where their testicles used to be.

How quickly does it work?

Your dog may still have some sperm in the system, so you have to assume he may be fertile for up to six weeks (although it is unlikely). Testosterone levels will gradually reduce over about 6 weeks over which time there should be a reduction in sexual behaviours.

If you want advice about getting your dog castrated, talk to one of our vets.