Neutering a dog (castrating and spaying)

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.

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.

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.

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.

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.

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.

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.

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.

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 affects around 0.7 – 3% 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.

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.

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.

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:

• Neutered females are 2 to 3 times as likely to develop urinary incontinence than entire bitches.
• Dogs neutered before 6 months of age are twice as likely to develop urinary incontinence than dogs that are neutered between 6 and 12 months
• Certain breeds have a higher risk of urinary incontinence, including:
  • Boxers
  • Dalmatians
  • Dobermann
  • English Springer Spaniels
  • Hungarian Vizslas
  • Irish Setters
  • Shar-Pei
  • Weimaraners
• Heavier dogs were also more at risk of urinary incontinence

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.

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.

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.

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.

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.