Neutering in dogs

Neutering in dogs: The why and how of castration and spaying

The question of when to neuter your dog is very difficult to answer, as there is no one answer that will suit all people and all dogs.

Our general advice is bitches should be allowed one season before neutering, and dogs can be neutered from 12 months of age. 

Members of our Lifetime Care Club receive a 20% discount off the cost of neutering.

However, there are many things to consider:

Sexual maturity

  • We would advise to wait until your dog is sexually mature before neutering.
  • Sexual maturity in male dogs is between six to nine months but in females it can be anywhere between six and 16 months.
  • Mounting does not reliably indicate the onset of puberty – this behaviour can be seen in both male and females from six weeks of age and can be related to stress, play, over stimulation or sexual behaviours.

Breed and size

Research has shown certain breeds should be left to at least two years of age before neutering, based on findings regarding increased risk of joint disorders and cancers.

We would recommend neutering at:

  • 24 months of age for large breed dogs (>25kg)
  • 18 months of age for medium breed dogs (15-25kg)
  • 12 months of age for small breed dogs (<15kg)

Many health problems can be contributed to weight gain, so regardless of neutering status it is very important not to allow your dog to become overweight.


In male dogs:

  • Testosterone is recognised as a confidence giver so the sudden loss of this after castration may trigger an increased fear response. With nervous dogs, we would suggest waiting a little longer if there are no health or safety reasons for neutering, to allow them to build their confidence before considering castration.
  • Testosterone can drive certain behaviours, including exploration, urine marking and sexual behaviour. Restricting these behaviours can lead to stress and frustration in an uncastrated male, so here castration may be useful.
  • If you are unsure whether surgical castration is right for your dog, we can consider medically castrating him first – which lasts six  months – to assess how his behaviour changes. However, there is unfortunately limited research on the reliability of the male implant altering a dogs behaviour.

In female dogs:

  • All female dogs have a phantom pregnancy after their season, even if they are not showing any signs. These include mammary development, discharge from the teats, nesting behaviours, neediness, loss of appetite, resource guarding or aggression. It is important to wait until there are no behavioural or physical signs of phantom pregnancy before spaying. This is approximately 12 weeks after the end of their season.

If you have any questions or require advice, please contact our team for a chat, or book an appointment online today.