Spaying dogs: the procedure

Not sure whether you should have your dog spayed? Wondering what the operation entails? Read this guide to find out when, why and how to have her spayed.

8th February 2015

When should you book the operation?

Once you’ve made the decision to have your bitch spayed, the next thing to do is decide when to schedule the operation. Opinion varies greatly as to the optimum time for spaying, but it is generally accepted that before the age of six months a bitch isn’t developed enough physically or hormonally. Bitches need a healthy balance of oestrogen and thyroid hormones T3 and T4 for normal growth, and these hormones only begin production when your bitch is approaching sexual maturity. Too little oestrogen can also lead to urinary incontinence in later life.

Some people will say that after six months is fine, regardless of whether she has had her first season yet. The benefit of spaying at this time is that you hugely reduce the risk of an unwanted pregnancy. It also allows a little more flexibility with the timing of the operation. A potential concern is that you cannot be certain that her growth hormones are in production.

Waiting until after the first season increases the risk of an accidental pregnancy, but guarantees that your bitch is sexually mature and therefore will have a healthy balance of hormones. The downside to this is that once your bitch starts her seasons there will be times when a spay will be inadvisable, i.e. when she is approaching a season, in heat, or eight weeks afterwards. This is because in the time leading up to (and during) a heat, the blood vessels supplying the reproductive organs are enlarged, which increases the risks associated with surgery. In the eight weeks after a season, your bitch may experience a “phantom pregnancy” as a result of a hormone imbalance. Spaying her during this time would cause a rapid change in hormone levels, which could be a confusing or even distressing experience for her. The best thing to do is have a chat with your vet, who will be able to advise you.

Before the operation

You will need to visit your vet so that he can give your bitch a health check and make sure there is nothing preventing the operation from going ahead. Your vet will be able to tell you whether your bitch is the optimum weight for the operation. Carrying excess body fat can make the surgery more risky, so if your bitch is overweight the vet will recommend that she slim down in advance of the operation. Your vet will also conduct a blood test to rule out any illnesses or abnormalities that could affect the safety of the anaesthetic.

On the day of the surgery your bitch should not have breakfast and, depending on the instruction of your vet, should be starved of food and water for a number of hours beforehand. This is to minimise the risk of vomiting and the complications that relate to that. It would also be advisable to take your bitch for a good long walk before heading to the vet. This gives her the chance to empty her bowel and bladder as well as letting her expend some energy, as this should help her to stay calm. It is also a good time for you to consider any last-minute questions you might have so you can ask the vet or nurse before the operation.

On arrival

When you get to the surgery you will check your bitch in with a receptionist, veterinary nurse or the vet themselves. This is your opportunity to voice any concerns or discuss any questions you may have. You should also confirm your telephone numbers so that you can be contacted quickly in case anything needs to be discussed with you during, or after, the operation.

The anaesthetic

The vet or nurse will weigh your bitch to calculate accurate doses of any medicines or anaesthetic needed to make sure the pain relief is as effective as possible. Her heart will be checked and, if the vet is satisfied, she will be given an injection containing a combination of drugs which will make her start to feel drowsy. This will ensure that the anaesthetic can be administered smoothly and that the pain relief is as effective as possible.

In most cases the anaesthetic is initially injected into a vein in the front leg. This form  is fast-acting but the effects are quite short lived, so in the majority of cases a gaseous anaesthetic is used to keep your bitch asleep. Inhaled anaesthetic is easy to control over a period of time, and is the safest way to keep your pet anaesthetised for the duration of the surgery. The gas will be delivered via a tube placed down your bitch’s windpipe.


Once your pet is safely asleep, the vet nurse will start preparing the site of the incision. Depending on the preference of your vet, this could either be in the centre of your pet’s tummy or to the side.  The area will be shaved and thoroughly cleaned. This not only helps to keep the area clear and hygienic during the operation, but also means that it will be easier to keep clean post-op.

The operation

The surgeon will use sterilised instruments to carefully open the abdomen and remove the ovaries and uterus. This is done in stages to make the surgery as safe as possible and to make sure that everything is under control at every step of the way. Once the reproductive organs have been safely removed the vet will stitch up the wound, either with internal or external stitches. The wound will be dressed to keep it sterile, before the anaesthetic gas is slowly reduced.

As your bitch slowly starts to wake, the tube is removed from the windpipe. She will be constantly monitored and additional pain-relieving drugs will be given as needed.

Immediate recovery

Just like humans, animals can be a little unsteady or sleepy as they wake from anaesthetic. To give her a gentle awakening, she will be placed in a cage with comfortable bedding and kept under observation. She is likely to sleep it off for the majority of the day.

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