Why do vets recommend castration – A behaviour perspective

Why do vets recommend castration for dogs with behaviour issues and when will castration help?

This article does not look at the medical aspects of castration, the risks associated with castration or the population control aspects of dog castration. We are only considering it from a behaviour perspective.

What is castration?

There are a few places you can get a definition of castration. In dogs it is removal of the testes by surgery. There are other forms of castration but we are not talking about those here. Removing the testes (balls) means that the hormones that give male dogs some of their male characteristics are removed.

What are the behavioural effects of castrating a normal, healthy dog?

The important thing to remember here is that all dogs are not the same and all dogs don’t read the text books. We are talking about an average dog (in reality no such dog exists).

In a study by Eniko, Kubinyi and his colleagues in 2009, they found that castrated dogs were calmer than their non castrated counterparts. They also showed that castrated dogs calm down more with age than uncastrated dogs. Obviously age, training, age at acquisition of the dog etc. all have an effect on how calm an adult dog will be.

They showed that if you played with your intact dog more often they were more likely to be calmer in general but this effect is not seen to the same extent in castrated dogs.

Castration also had an effect on sociability of the dogs when they lived with two or more dogs. Castrated dogs with two or more dogs in the household were less sociable than their uncastrated counterparts.

They also looked at the effect that time spent with owner has on these dogs. In general castrated dogs were bolder but when dogs spend more than 3 h a day with their owner castrated dogs were less bold than intact dogs and boldness decreased the longer dogs spent with their owners irrespective of castration status. As the authors point out this could be because owners that spend more than 3 hours a day with their dogs are more likely to live in apartments or flats and not have access to gardens and this has a direct influence on how bold a dog is.

(define bold and calm)

The same study found that uncastrated males were more trainable than their castrated equivalents. In this case the authors clearly state that one has to question whether they were castrated in an attempt to influence training and calmness i.e. the dogs were already untrainable or boisterous and castration was attempted as a solution. Unfortunately the study did not report on whether they asked the various owner the reason for castrating their dog as this would have helped in filtering out the dogs with prior issues.

Brennen published a review article that speaks about the benefits and risks of neutering dogs and cats. According to the literature that Brennen found, dogs that were not castrated were more likely to be involved in aggressive type behaviour. The article goes on to say that reductions in aggression are reported after castration. The article also reported that roaming behaviour decreased, aggression between males decreased and both urine marking and mounting decreased following castration.

What about dogs with pathology or some behavioural problem?

Castration clearly does not cure all when it comes to behaviour issues. A study done by Maarschalkerweerd and peers on the effects of dogs that were castrated as a result of behaviour problems makes it clear that the results of castration can be variable. The problem must be diagnosed by a qualified competent person for the castration to have the expected outcome and even then it is not fool proof. The reason for this is that if a dog has learnt the behaviour such as leg humping and it likes the reaction that it gets from doing it. Another example is that if the dog roams and is then castrated it is likely to still roam if the home is not entertaining enough.

Maarschalkerweerd’s study found that castration has the strongest influence on problems that are more likely to occur in male dogs (sexually dimorphic behaviour patterns) e.g.

  • status-related aggression
  • urine marking (indoors and outdoors)
  • mounting
  • roaming

age, and pack behaviour (if there is more than one dog in the household). Additional benefits of castration include a reduction in the dog’s general activity level, decreased preparatory arousal and a decline in the dog’s ability to focus its attention fully on the target of attack. As a result, it is much easier for the owner to disrupt and manage or control the dog’s agonistic intentions. However, castration is not the ultimate remedy in dog-handling.

Any decision in this respect should be based on a precise behaviour- related indication. Otherwise, such surgery may well be considered as unethical in terms of behaviour.


  1. Dog and owner demographic characteristics and dog personality trait associations by Eniko˝ Kubinyi , Borbála Turcsán and Ádám Miklósi published in the Behavioural Processes 81 (2009) 392–401 journal in 2009
  2. Evaluating the benefits and risks of neutering dogs and cats by Brennen McKenzie published in CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 2010 5, No. 045 in 2010
  3. Castration of dogs from the standpoint of behaviour therapy by
  4. Influence of orchiectomy on canine behaviour by Maarschalkerweerd RJ et all published in The Veterinary record 140:24 1997 Jun 14 pg 617-9

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