Neutering a dog (castrating and spaying)

Neutering (e.g. castrating or spaying) your dog is a big decision to make, but is it right for your dog and you? To help you make a well-informed decision, it’s important that you understand the benefits neutering can bring, whether there are any risks of it affecting your dog’s health, behaviour or weight, what age your dog can have it done and how much the procedure costs. Making any decision that involves an operation should never be taken lightly, so find out more below and always talk to your vet about whether neutering is right for you and your dog.

What is neutering?

Neutering, sometimes called sterilisation, ‘de-sexing’ or ‘fixing’, is a common type of surgery that permanently stops your dog from being able to have puppies. In male dogs, this is known as castration and involves the testicles (testes) being removed. In females, the ovaries and usually the uterus are taken out and is called spaying. Although both procedures involve a general anaesthetic, your dog is likely to be back home with you on the same day as their operation.

How much does it cost to neuter a dog?

Neutering usually costs between £100 and £400, depending on your dog’s breed, size and sex.

The cost of neutering may be different for some dogs because:

  • Spaying a female is more complicated and requires surgery on internal organs. Spaying a female is often more expensive than castrating a male
  • Certain operations may be more difficult, such as castrating a male with a retained testicle
  • Larger dogs may need more anaesthetic and the operation may take longer because of their size

Can I get my dog neutered for free in the UK?

Some veterinary charities, such as the Blue Cross, The Mayhew Animal Home, RSPCA and some rescue organisations may offer free or low-cost neutering to pet owners that are eligible.

Is the operation safe?

Neutering is one of the most common types of surgery carried out on dogs and is performed at most veterinary practices every day. As with any operation, complications can occur, but the risks involved in this procedure are low. During your dog’s operation, they will be monitored carefully, and your vet and their team will keep a close eye on your dog to keep them safe. If you’re concerned about your dog’s operation, then speak to your vet beforehand, and they can talk to you about the risks involved.

What’s the best age to neuter my dog?

The right age to have your dog neutered depends on your dog’s breed, size and sex. The ‘best’ age to have this done is often debated, but your vet will be able to guide you using the latest research and guidelines.

Most dogs are usually neutered between six months and two years of age. To completely rule out unwanted pregnancies, you can have your dog neutered before they’re sexually mature. The age a dog sexually and physically matures often depends on what breed they are. Generally speaking, smaller dogs may be sexually mature at an earlier age than a larger breed. For some breeds, your vet may suggest waiting until your dog is older, as earlier neutering in some dogs has been linked to certain health issues.

Can my female dog (bitch) be spayed before her first season?

Some vets routinely spay dogs before their first season to reduce their risk of breast (mammary) cancer and womb infections and to guarantee they can’t accidentally get pregnant. Other vets will wait until a dog has had their first season so that the hormones produced by their ovaries can continue to help them mature, which reduces the risk of some health conditions developing later in life.

So, which one is right?

The British Veterinary Association say that there is ‘currently insufficient scientific evidence to form a position on the early neutering of dogs and bitches’, which means that, at the moment, there isn’t enough evidence to say which is better. Talk to your vet and to your breeder about the pros and cons of both to help you decide when the best time is to neuter your dog.

Should I let my female dog have a litter before getting them spayed?

There are no known health benefits to letting your dog have a litter before they are neutered and so shouldn’t play a part in your decision to neuter. Pregnancy and whelping can come with complications and caring for puppies can be expensive, time consuming and hard work. You should only ever breed from your dog after you’ve thought about it carefully and have decided that it’s the right thing for you, your dog and the breed.

Should I get my puppy neutered?

All owners should carefully consider whether neutering is right for the dog and for them. Although it’s very common for people to have their dog neutered, it’s important to remember that it’s a type of surgery, so needs to be carefully considered. It’s important to weigh up the pros and cons, do your research and talk to your vet about any concerns you have. Many people choose to have their dog neutered to eliminate the risk of pregnancy, curb certain behaviours and reduce the risk of some health issues. These benefits should be compared with other factors, such as the possibility of weight gain, urinary incontinence, change of coat length and texture and certain breed specific risks. Always involve your vet in these discussions; they are best placed to talk to you about the latest research and veterinary guidance and will be able to discuss the pros and cons with you.

What are the benefits of neutering?

Choosing to have your dog neutered has the following benefits:

Preventing unwanted pregnancies

This is obvious, but having your dog neutered rules out the possibility that they can become pregnant or can get another dog pregnant. Having puppies can be expensive, time consuming and is not without its risks, so should be avoided, unless it’s something you’ve considered carefully.

Spaying a female dog also eliminates the risk of phantom pregnancies. These can occur after a season and can cause a dog that is not pregnant to behave or show signs as if they were, including producing milk. Although phantom pregnancies are rarely serious, they can still cause your dog to behave differently and may require the help of your vet.

Changing some undesirable behaviours

A dog’s testes produce testosterone, so once castrated, males may be less likely to show behaviours that are influenced by this hormone, such as:

  • Trying to mount things
  • Scent marking their territory
  • Running away to find a female in heat

Some say that neutering your dog makes them less likely to be aggressive or fight. Lots of factors influence how a dog behaves, so neutering your dog may not change the way they act, or can sometimes, particularly in the example of aggressive dogs or dogs with low confidence, make them worse. If you’re concerned about your dog’s behaviour, you should always speak to your vet and a trained animal behaviourist.

Reducing risks of some cancers

Neutering your dog can prevent them from getting some cancers and can greatly reduce the risk of others. Castrated male dogs no longer have testicles, so are not able to develop testicular cancer. Similarly, spayed females have had their ovaries and uterus removed and so are unable to develop ovarian or uterine cancer.

Neutering female dogs can also reduce their risk of developing breast cancer (also known as mammary cancer), which can often be fatal or expensive to treat. However, it is worth researching any links between neutering and the risk of other cancers in your breed, as some research has found that neutering can increase the risk of certain cancers. For more information, speak to your vet or a breed health expert, such as your breed’s breed health co-ordinator.


Minimising some infections and diseases

Spayed females are unable to develop pyometra, an infection of the womb that often requires surgery and can be fatal.

Castrated males have a greatly reduced risk of developing an enlarged prostate and prostate infections.

Stopping seasons

A season is the change that happens to a female dog’s body that enables them to become pregnant. During this time, there may be some behavioural changes (e.g., showing more interest in males and mounting objects) and usually physical changes, such as bleeding from the vulva. Some dogs may only produce a very small amount of bloody discharge, while others may have considerably more. Seasons can occur as early as ix months old, but some may be 2 years before they have a season. Most dogs usually have a season twice a year, but this may vary from dog to dog and by breed. Their season may last for 2 to 4 weeks, but they often only bleed for around ten days.

Having your dog neutered stops them from having any further seasons, which means that there will be no bloody discharge to clean up. Also, when a dog is in heat, they produce a scent that attracts males, so spaying a female means that they are less likely to attract dogs that wish to mate with her.

Find out more about dog seasons.

Preventing inherited diseases from being passed on

Most dogs can be bred from, so long as they’re matched to a suitable mate. However, dogs that could pass on any genetic conditions that might affect the health or welfare of their puppies should never knowingly be bred from. Neutering these dogs can help prevent future generations of dogs being affected.

Considerations to think about

Although there are many benefits to the average dog owner having their dog neutered, it may not be suitable for every dog. Below are some things to think about if you’re considering having your dog neutered.

Neutering is permanent

Neutering your dog is irreversible, so will not be appropriate if you’re thinking of breeding from your dog in the future. Most dog owners do not breed from their dogs and so breeding is not a consideration that applies to many owners.

Weight gain

Having your dog neutered can change their metabolism, which means that they may need less calories than before they were neutered. Having a slower metabolism can mean that it’s easier for them to put on weight. Having a slower metabolism can be managed by reducing the amount of food they’re given or by changing the type of food they eat. Your vet will be able to tell you how to reduce the risk of your dog becoming overweight after neutering.

Find out more about feeding after neutering.

Possible links to other health issues

Although there are many proven health benefits to neutering, some research has found links between neutering/early neutering and a number of health issues, such as back issues in Dachshunds or joint problems and some cancers in several breeds (e.g. Golden Retrievers, Labrador Retrievers, German Shepherd dogs and Hungarian Vizslas). The risk that neutering poses to individual dogs seems to be linked to the age that they are neutered and their breed. Your vet will be able to tell you whether there are any specific risks linked to your dog’s breed and how these risks compare to the benefits of having them neutered. Your breed’s breed health co-ordinator may also have information on breed specific risks, or you can look at the links to research that we have added throughout this article.

Urinary incontinence

Urinary incontinence affects around 0.73% of female dogs in the UK. This condition can cause them to find it difficult to always control when they go to the toilet. Recent research has found that spayed females are two to three times more likely to develop urinary incontinence than entire bitches, and that bitches that are neutered at a younger age (less than 6 months) have an even higher risk still. Certain breeds may be more at risk than others, so it’s worth talking to your vet about the risks posed to your dog.

Changes to their coat

In some breeds, neutering your dog can change the texture of their coat and is said to sometimes alter the colour slightly in others. Some people say that after neutering their dog’s coat became thicker, woollier, fuzzier or even softer, and may be a result of changes in hormone levels. How your dog’s coat looks or feels may not play a big part in your decision to neuter, unless you’re thinking about taking part in dog showing. If you’re concerned about a change to your dog’s coat then speak to your vet, breeder or local breed club for advice.

Always talk to your vet

If you’re thinking of having your dog neutered, the best person to discuss this with is your vet. Your vet will be able to give you reliable, research-based information and will be able to answer any questions you may have about possible pros and cons, what the procedure involves, how much it costs and how quickly your dog will recover.

Frequently asked questions

Will my dog become overweight after they’re neutered?

Being neutered doesn’t directly cause your dog to gain weight, but it does change their hormones, which in turn reduces their metabolism, often meaning they need around 30 per cent less calories than before their operation. If your dog maintains their usual diet, then you may find that they begin to put on weight. It’s important that once they have fully recovered from their surgery you help them stay fit and healthy with regular exercise, but you should also talk to your vet about changes to their diet, such as changes in portion sizes or giving them food that is lower in calories and specifically designed for neutered dogs.

Find out more about feeding after neutering.

Does neutering cause urinary incontinence?

Dogs that are affected by urinary incontinence cannot always control when they wee, causing them to occasionally leak urine. Females are more likely to develop this condition than males, affecting between 0.7 - 3 per cent of female dogs in England.

Two recent large studies by the Royal Veterinary College, both partially funded by The Kennel Club Charitable Trust, found that:

It’s important to consider all factors when deciding whether neutering is right for you and your dog. If you’re concerned about the risk of your dog developing urinary incontinence after neutering, particularly if you own a breed that is more at risk or if your dog is heavier, then you should speak to your vet. Research into the benefits and possible disadvantages of neutering is ongoing and your vet is the best person to talk to about the latest recommendations.

Can neutering change my dog’s behaviour?

The way your dog behaves is influenced by their breed, sex, socialisation and training. Whether they’re neutered can affect a few behaviours, including:

  • Scent marking
  • Looking for potential mates or running off to find a mate

Some people say that neutering can reduce barking and humping, but there are many reasons that dogs might show both of these behaviours, such as excitement or out of habit, and neutering may not affect them at all.

Although neutering can improve some behaviours, it can make others worse. In male dogs, testosterone can give them a confidence boost, so removing their testicles, which are the main producer of their testosterone, can make some nervous and anxious dogs more fearful and more likely to be aggressive when stressed. A dog’s behaviour is a complex issue that’s affected by lots of different things, so it’s important to talk to your vet about how neutering can affect your dog, especially if you have any concerns about their behaviour.

Will neutering change my dog’s personality?

It’s unlikely that your dog’s personality will change, so long as they have been well socialised, are generally happy and are confident. Neutering can sometimes change certain behaviours that are affected by a dog’s sex hormones, such as aggression, territory marking etc., but these behaviours are separate from a dog’s personality.

Does neutering a dog calm them down?

Some people say that neutering a dog can help to ‘calm them down’, but there is little scientific evidence for this. If you feel that your dog is over-confident, ignoring you when called, aggressive or is acting in a way that you don’t think is right, then it’s important to get help and talk to your vet or an animal behaviourist. They will be able to give you advice on how to help your dog and about the importance of training and positive reinforcement. Neutering is not a sure-fire way of resolving behavioural issues and can sometimes make them worse.

Can I compete in dog shows and canine activities if my dog is neutered?

Yes. If your dog is neutered, they can still compete in dog showing and other canine activities. However, you will need to inform The Kennel Club that the dog has been neutered. You do not need to get a letter from your vet for this, but you do need to let us know.

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