The Behavioural Effects and Health Benefits of Castrating Dogs

Castration is the same surgical procedure as neutering or sterilization where both testes are removed. In technical terms it is referred to as an orchidectomy and is a minor operation carried out only by a qualified veterinarian, under general anaesthetic, under strict aseptic conditions. The basic principle of this technique is to remove 99% of the dog’s testosterone levels.

Once the operation is done there is no going back so owners must be convinced about their decision.

The only dogs that should never be considered for sterilization are, obviously, genetically valuable individuals with desirable physical, health and temperament traits and those that may be an anaesthetic risk. The former are often show dogs. Otherwise, there is no reason why every male dog should not be neutered.

Castration may be considered as a prophylaxis for health hazards and potential behaviour problems or, on the advice of a veterinarian, as a treatment for emerging medical problems or existing behaviour disorders.

Sterilising male dogs has numerous health benefits. From a veterinary medical perspective it prevents:

  • Prostate infection, prostate cysts and prostate cancer
  • Certain types of hormonally-influenced cancers elsewhere in and on the body e.g. peri-anal tumours
  • Serious bite wound infections as neutering reduces aggression
  • Retained testicles from becoming cancerous

It is not uncommon for dogs to develop testicle infections (orchitis) for which castration would be a relief and cure.

Some of the behaviour problems cured, prevented or reduced by castration include:

  • Leg lifting and urine marking, indoors and outdoors; scent marking
  • Mounting
  • Aggression
  • Chasing
  • Disobedience
  • Escaping
  • Possessiveness over toys, food and stolen articles
  • Growling at owners and other dogs
  • Boisterousness
  • Territoriality
  • Puppy challenging an older male
  • Fighting between 2 male dogs

Main reasons for neutering dogs:

  1. Pet owner’s responsibility towards animal population control. Thousands of homeless and unwanted puppies are euthanased every year from negligent, organised or accidental matings. Most animal welfare organizations have a policy of sterilizing before homing, sometimes as early as 8-12 weeks of age. This forms part of the adoption agreement. Due to people’s lack of compliance the recommended age of 6 months for castration is often ignored or forgotten.
  2. Health reasons
  3. Preventing unwanted dogs at rescue homes which are usually 1-4 years of age, intact males mostly with one or more behaviour disorders.
  4. Behaviour problems. Dog owners are often taken by surprise when objectionable changes in canine behaviour occur between 6 and 7 months up to 3 years of age. Not all males, not all breeds are difficult as they mature but one should be aware of the possibility.

The confined, unnatural environmental circumstances of modern day living makes life much more frustrating for intact male dogs which is one of the reasons that so many people get attacked by “man’s best friend”. It is not surprising that canine drives and instincts may occur at unacceptable times and inappropriate places with possible antisocial or even dangerous consequences. Sterilisation markedly reduces the anxiety of boredom and lack of stimulation. The drop in hormonal levels in the neutered male loses most of the incentives for sexually dimorphic behaviour such as urine marking, many forms of aggression, mounting patterns, roaming, mate- seeking (behaviour expected from male dogs).

If there is a conflict between two male dogs on the same property the neutering of both individuals will prove to be, in general,  highly successful.

The expected response from castration varies from 10 days to 2 months.

Castration is not a cure for all forms of aggression e.g. fear aggression.

Castration is not a remedy for other behaviour problems e.g. lack of socialization, nervousness, destructiveness etc.

In the event of having to sterilize a companion animal to control certain unacceptable behaviour patterns, an accredited animal behaviourist or veterinarian must be consulted regarding all the other approaches required to solve the problem. Often the operation is a recommendation in conjunction with owner behaviour modification and environmental alteration.

It is a fallacy that allowing a dog to mate will stop problem behaviours. Contact with bitches can, in fact, make matters worse due to heightened hormonal arousal, protective instincts.

It is not cruel to deny a dog the sexual desires. The male is only attracted to a female when she is in season (oestrus), secreting pheromones, luring the dog by idiosyncratic odours. There is no physical, emotional or mental attraction! For these reasons the desire to mate is by odoriferous chemicals only. What the nose does not smell the heart does not feel! There is a macho mental state of many men who suffer from castration anxiety where they feel that their dog must experience sex. This is anthropomorphic (attributing human attributes to animals). Many men refuse the idea of castrating their dogs as it may be a slight on their own manhood and often cross their own legs and grimace at the mere thought of their own sex lives. These men will readily have their bitches spayed and never give a thought to the wife having a hysterectomy.


Castration may be carried out at any age from 8 weeks onwards provided there is complete visual of both testes in the scrotum. This is often a policy amongst animal welfare groups. There are less side-effects, quicker recovery and well tolerated by the puppy.

In most instances castration is recommended at 6 months i.e. just prior to puberty.

Castrated dogs are often easier to train. Neutering does not make them lethargic. Dogs do not know that they have been sterilized. Sterilised dogs do not become wimps.

The disadvantages of castration are few but include:

  • Coat changes in certain individuals

Weight gain, which is mostly due to lack of exercise and over-feeding

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