Neutering’s behavioural effects

There can be some benefits to neutering your dog – preventing unplanned litters, reducing the risk of testicular and mammary tumours… Many also add behavioural benefits to that list, particularly with male dogs. But is it true that neutering can help your dog’s behaviour? Here’s everything we currently know on that particular topic.

How much does dog behaviour change after neutering?

It’s a myth that neutering will make a dog calmer. Often, “boisterous” dogs require their needs to be met through the likes of physical and mental stimulation as well as adequate sleep. Satisfy those needs in appropriate ways, reward calmness through positive reinforcement training, and you’re likely to see less excitability. 

However, some behavioural issues may improve through neutering. Again, these are usually with male dogs due to the effects of testosterone. This hormone can lead to more frequent humping, urine marking and roaming – essentially any behaviour that is sexually driven. It can also make aggression more likely and more intense when a dog feels threatened or frustrated, particularly in the case of male competition. 

Castrating a dog stops testosterone from being produced. Therefore, it can reduce the frequency of these behaviours, but only if they were caused by testosterone. Similarly, if the dog has been reinforced for a certain behaviour over time, castration may also have less of an effect.

Which brings me onto the following…

Does a dog’s personality change after neutering?

Behaviour is incredibly complex and it isn’t just influenced by hormones. The likes of genetics, environment and previous learning will all affect the way your dog behaves. So even if a particular behaviour was influenced by testosterone, castration may not stop that behaviour entirely.

(This has been particularly noted with aggression, with researchers concluding that there’s currently no way to accurately predict the effects of castration on aggression.)

Plus, it’s important to remember that each dog has an individual personality and temperament – just like humans. And no medical procedure will change that. 

Instead of looking for a “quick fix” (which unfortunately doesn’t exist with the majority of behavioural issues), you’ll need to think about why your dog is behaving in a certain way. It can be extremely difficult to work this out, so speak to a behaviourist.

They will ask your vet to fill out a referral form and check there are no underlying health issues contributing to the behaviour. Once the medical side has been given the all clear, a behaviourist can then help you work out the underlying emotion and motivation and come up with a plan to address the issue.

For example, in some dogs, humping can be a response to stress or even a way of seeking attention, rather than a purely sexual behaviour. And excessive urine marking may also be due to anxiety or stress, or a sign that your dog isn’t fully house trained. 

Dog neutering can make some behavioural issues worse

One of the most concerning parts of using neutering as a behavioural strategy is that it can worsen some issues. While testosterone can lead to “undesirable” sexual behaviours, it’s also linked to more self-confidence in dogs. Therefore, taking it away from an already nervous dog can lead to increased fearfulness.

It’s worth noting here that some aggressive behaviour can actually be rooted in fear or anxiety, so neutering may potentially lead to an increase in fear-based aggression. (Be aware that some male dogs may show increased reactivity in the short term after castration due to the body continuing to send signals to the testes, which are of course no longer there.) 

Similarly, spaying a female dog who’s going through a pseudopregnancy can be problematic, with reports of the physical and behavioural signs persisting. There have also been reports of dog-to-dog aggression in the same house worsening when spaying occurred at an early age. 

Where to go from here

Neutering for health-related reasons or ethics is a different ballgame to neutering for behavioural reasons. While neutering may help some behavioural issues, it may have no effect on others and can even make some problems worse. 

In a nutshell, dog neutering may help the following behaviours as long as they’re directly influenced by sex hormones:

* Humping or mounting

* Roaming or regularly distracted by female dogs

* Urine marking

* Competitive aggression with other males

However, if other factors are contributing to the behaviour, you may not notice a dramatic change.

And the following can worsen as a result of dog neutering:

* General nervousness (particularly in males)

* Fears or phobias (particularly in males)

* Fear aggression (particularly in males)

* Pseudopregnancy signs 

* Inter-household dog-dog aggression (in females)

Unfortunately, there are no guarantees and we need to remember that each dog has their own individual genes, personality, environment and learning experiences. Due to the likes of fear periods, it’s also important to consider the best age to neuter. In some cases, it may be better to wait until your dog is emotionally mature.

If you’re worried about your male dog’s behaviour after neutering but would like to neuter for another reason, you can try a temporary chemical castration for dogs that lasts for around six months. 

Speak to your vet and a qualified behaviourist before making a final decision and remember to take the entire picture into account.