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As a dog trainer, I often get asked about the benefits and drawbacks of dog castration. It’s a controversial topic that can divide opinions among dog owners, trainers, and veterinarians. As someone who has ummed and arrrred over whether to castrate my own dogs, researching into what would be best for them, I’ll be sharing my personal perspective on castration and the different options and outcomes to consider. Castration, won't be right for all dogs, but it is something to contemplate and we will be looking at the pros and cons of all options.

When is the right time?

If you are mulling over castration or spaying, you should first let your dog go through adolescence, especially in large breed dogs. They need time for their bones to fuse properly and without their sexual hormones this can impact growth. Current guidance says that a dog should be at least 2 years before neutering.

But, let’s discuss what castration entails. A physical castration is a surgical procedure that involves the removal of testicles in male dogs. The procedure is usually performed under general anaesthesia, and it’s a permanent method of sterilisation. The cost of a full castration will be between £150 and £300 depending on your dog size and the vet completing the procedure.

How it works

It is a relatively small procedure and dogs tend to recover quickly. Testosterone cannot be produced once the testicals are gone, so once the hormones that are already in their body have worn off that's it. If you have a dog that has a nervous or fearful disposition a permanent castration could cause them to become fear reactive in some situations. The Testosterone in their body acts like the bravery hormone giving them confidence in certain situations.

If you have doubts at to whether a full castration is the right thing for your dog you can also opt for a chemical castration, this is an implant injected underneath the dogs skin that temporarily stops testosterone from being produced in the body. The name of this implant is called Suprelorin and can have mixed reviews in vets practices. This method of sterilisation is temporary and can last between 6 and 12 months and can be expensive if you continue to use this every year. Roughly £150 a pop. Although temporary it can give you a good indicator as to whether a castration will impact your dogs behaviour either positively or negatively. If you opt for this option there is a 2 week surge of testosterone, so you may see behaviour increase rather than diminish initially. This 2 week period should be used as a reset button taking them back to doing socialisation training. Making sure that they do not have any negative experiences whilst their hormones are so unsettled. To avoid dog heavy locations or engaging with dogs you do not know well.

So lets take a look at the possible pros and cons in more detail.


  • Marking. You may notice that once your dog is castrated they do not feel the need to make urination marks as frequently, or they may stop altogether

  • Roaming. You may find that your dog no longer roams or catches scents of bitches in season and so will stay closer to you.

  • Calmer around other dogs, particularly male. You may find that your dog no longer feels the need to protect his space in the same way he used to and is able to get on with other male dogs in a calmer way

  • Energy levels. Some dogs do calm after castration. This should not be the only reason to castrate as it is not a guarantee. You may just have a high energy dog.

  • Protection from testicular cancer


  • Prostate problems. It could cause some prostate issues

  • Weight gain. It slows their metabolism and can cause them to gain weight. It will be important to monitor their food intake and ration appropriately.

  • Fear reactivity intensified. If your dog is of a nervous disposition it can cause them to become even more reactive.

  • Hypothyroidism. There is some evidence to suggest castrating can increase the possibility of this in your dogs.

My own personal experience of castrating a dog was with my Labrador. He sometimes displayed nervousness around other male dogs, putting his hackles up and a subtle growl to warn them off. As he got older he became more and more bitch obsessed. If he caught wind of a bitch in season he wailed, needing to check out every single dog he met and would sometimes run close to half a mile away from me to find his potential mate. This caused us huge problems when training. If we were in a dog heavy environment, he just could not focus and he would become more and more overstimulated. It was impacting our work and my relationship with him - I was so frustrated. When Jackson was 4, we went to the vet to discuss the chemical implant. I was reluctant to fully castrate him because of his slight nervousness around some dogs and I was anxious that it could cause him to become reactive and not be able to work as a therapy dog. The vet heard my concerns and agreed to chemically castrate him for 6 months as a trial.

We kept Jackson on lead for 2 weeks after this procedure and kept him away from all dogs for a further 2 weeks after that. We wanted to make 100% sure he would not have a negative experience or cause him to become over adrenalised. After 1 month we saw notable differences. He was not marking as frequently, he was able to disengage from other dogs at the park and his recall improved. He does not roam any more and for the most part he can take or leave other dogs on a walk. (Unless he sees another Labrador of course)! He has gained a bit of weight but only 4kg and we make sure he does not eat to much to compensate for this. He is still a healthy 30KG.

Before you make the call to castrate your dog you should first consider these things:

  • Age and health of your dog currently

  • Behaviour - are you castrating to solve a behavioural problem that can be trained?

  • Lifestyle - Do you live with an unswayed bitch? Will you be taking your dog to places where other dogs go?

Castration is a personal choice and there is lots to consider when doing it. For some dogs if their behaviour is good, they're training up to par and they aren't being a nuisance to other dogs then they won't need to be castrated ever. For others it will be the making of them. If you are in any doubt as to whether it's the right thing then discuss it with your vet or qualified behaviourist, and perhaps try the implant. If the worst happens then at least you know it's reversible in a few months.

In conclusion, castration is a complex issue that requires careful consideration and understanding of the individual dog’s need and circumstances. As a trainer, I believe that castration should not be used as a substitute for training and behaviour modification and it should only be considered if it’s in the best interests of the dog’s health and wellbeing.

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