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To Spay or Neuter?

Spaying or neutering your Collie is a very personal decision, but one you will want to make based on the real facts surrounding the procedure. While most pet owners still elect to spay or neuter their Collie, there are a growing number who have decided to forgo the procedure entirely.


Those who do still want to neuter their pets, want to know what the best age for this is. Historically, vets have often performed what is called 'paediatric neutering' - performed on dogs who have not yet reached sexual or physical maturity. This was done in order to prevent 'pet overpopulation', by sterilising cats and dogs to prevent breeding. In the modern day, pet ownership has taken on a different role with dogs no longer 'free roaming' the streets, and the law dictating dogs must be under owner control in public. With their dogs under their control at all times, the responsible pet owner is far less likely to experience unplanned pregnancy, or for their intact boys to impregnate a neighbourhood dog. For this reason, responsible owners sometimes choose to spay and neuter after maturity, or not at all. 

Your Male Dog

Pros of Neutering

Reduces instinct to roam if there is a bitch in heat in his area.

Certain behavioural issues can be solved by neutering, such as hypersexuality and some forms of aggression, although not every behavioural issue can be solved by neutering.  (source A)

Removes the chance of unwanted mating and pregnancy if you also have an intact bitch.

Cons of Neutering

Neutering may increase the risk of obesity and weight gain in male dogs. (source  A, B)

Neutering leads to decreased activity levels in male dogs, and led to a 36% increase in resting time in one study. (source B)

Neutering increases a dog's risk of cancer and ruptured anterior cruciate ligament. (source C) However, in the Collie breed, recent studies show this effect might not be as pronounced as in other breeds. (source D)

Neutering causes coat changes in the male dog, which can lead to a longer coat length and a thicker, wooly coat, which may mat easier.

Neutering your dog will close off all possibility of breeding from him, if you ever decided you wanted to. However, you will still be able to show him, if you obtain a Permission to Show certification from the Kennel Club.

Your Female Dog

Pros of Spaying

Removes the chance of unwanted pregnancy, which can be costly, very time consuming, and could present a risk to the bitch of health concerns related to whelping and rearing a litter.


Spaying removes the risk of a dangerous and sometimes fatal condition called Pyometra.


Certain behavioural issues can be solved by neutering, such as hypersexuality and some forms of aggression, although not every behavioural issue can be solved by spaying.  (source A)

Cons of Spaying

The spay procedure can lead to Urinary Incontinence (inability to hold her bladder) in female dogs. (source D)

Spaying before a dog has reached their full physical maturity, leads to the dog growing taller and due to not being able to complete her normal heat cycles, she will not mature and fill out in the same way an intact bitch will. (source E)

Spaying alters the coat texture and quality in Rough Collies. The coat often becomes much longer and thicker, and may mat easier. (source F, and your bitch's breeder can advise further)

Spaying increases the risk for certain cancers (lymphoma, hyperadrenocorticism, mast cell tumor, hemangiosarcoma, and osteosarcoma). Studies suggest spaying before the age of 6 months could increase this risk in Collies by 40% (source C, D)


Spaying can increase the risk of weight gain and obesity in female dogs, due to an increased intake of food and more time spent resting. (source A) 


Spaying can sometimes impact temperament negatively. (source A)

Spaying your bitch will close off all possibility of ever breeding from her, if you ever decided to follow this path.


Source A -

'Behavioural problems in most cases are reduced or have even disappeared after neutering (male dogs 74%, female dogs 59%). At best, hypersexuality and connected problems are changed as expected. 49 of 80 aggressive male dogs and 25 of 47 female dogs are more gentle after neutering. 10 bitches appeared to be aggressive only after being neutered. Particularly feeding behaviour changes in 42% of the male dogs and 32% of the female dogs towards an increased intake of food, which also leads to an increase in body weight. This corresponds to decreasing activity, which is indicated by increasing time of rest (male dogs 36%, female dogs 18%) and decreasing motivation to move.'


Source B -

'An important and novel finding was that neutering increased the risk of being overweight or obese for male dogs.'

Source C -

'Neutering was significantly associated with an increased risk for males and females for cancers (hemangiosarcoma, hyperadrenocorticism, lymphoma, mast cell tumor, and osteosarcoma), ruptured anterior cruciate ligament and epilepsy. Intervertebral disk disease was associated with increased risk in females only. For elbow dysplasia, hip dysplasia, lens luxation, and patellar luxation neutering had no significant effect on the risk for those conditions.'

Source D -

'There was no evident increase of cancers in males with neutering, and in females, there was an increase of cancer to 40 percent in those spayed at <6 mo., which may have reached significance with a larger sample size. For females left intact, 4 percent were diagnosed with MC, and 16 percent were diagnosed with PYO. Of females spayed at 6–11 mo., 13 percent had UI.'

Source E -

'Growth plate closure was delayed (group I vs group III; P less than 0.000001; group II vs group III, P less than 0.000001) in all neutered dogs, as compared with sexually intact dogs. Growth plate closure was delayed longer (group I vs group II, P less than 0.000045) in dogs neutered at 7 weeks old, compared with dogs neutered at 7 months old. The rate of growth was unaffected by gonadectomy, but the extended growth period resulted in greater final radial/ulnar length in all male dogs and bitches neutered at 7 weeks.'

Source F -

Coat changes in the Spayed Bitch

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