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Seasons,spaying and neutering

  • Bethany Calhoum
  • Apr 14, 2025
  • 10 min read

Updated: Aug 14, 2025

Although many vets recommend neutering at 6 months of age, this is not necessarily in the best interest of the dog health, or behaviour-wise. A huge part of a vet’s income comes from ‘routine’ treatments, and the complications which come of them. Rescues tend to have in their contracts to neuter any dogs adopted under 6 months old, are to be neutered by the time they turn 6 months – this is to reduce risk of over population, but again is not necessarily in the best interest of the dog’s health of mental wellbeing. 

Timing 

According to the most recent studies into the right age to neuter at, the most beneficial time to neuter is after the dog turns two years of age. They suggest smaller breeds may cope ok health wise, If left until 18-24 months of age as they tend to mature quicker than larger breeds, but larger breeds, such as Border Collies, Retrievers, to Great Danes and Deerhounds do not mature until at least 24 months of age (with the age of maturity growing exponentially with size of dog). If you think about humans going through puberty, taking away their hormones would have detrimental effects to both health (now and in the future) and behaviour – all mammals need hormones for healthy growth and mental development. There’re some scientific journal articles in the ‘Bibliography’ section for some detailed research with all the scientific jargon included if interested. They are all studies on individual breeds as it is easier to control the study with fewer variables such as using different breeds. 


Health Cancers Testicular - Neutering eradicates the risk of testicular cancer, testicular cancer in entire males is actually rare. If a dog were to get testicular cancer, simply removing the dog’s gonads (reproductive organs – in the males’ case, testicles) at time of diagnosis will rid of the cancer. Always keep an eye on your dog’s testicles during your regular health checks/once overs (I give them at least once a week, more often during tick season) and look for irregularities in shape and feel. 


Hemangiosarcoma – this is a malignant tumour (cancer) which affects the lining of blood vessels, the most common being in the Spleen. It can however be found on any blood vessel, and often spread to the heart and lungs, particularly in aggressive cases. This is more common in castrated dogs and the risk of it is significantly increased by neutering before two years of age. Thankfully for owners of male dogs, it is significantly more common in spayed females than neutered males. 


Osteosarcoma – this is the most common cancer of the bone. When is spreads, it can lead to limb amputations, or death in the worst cases. In one study the increase in cases of osteosarcoma in neutered dogs vs entire dogs, was 2-fold! That’s twice as common! In another study, on rottweilers, the increase in risk of osteosarcoma between dogs neutered before 12 months of age and entire dogs was 3-4 times higher! 


Prostate Issues and Perianal Fistula 


Non-cancerous prostate and anal issues are higher in later years in entire dogs. Prostate cancer, however, seems to be at more of a risk in dogs neutered before two years of age. This is a topic which is still being explored as yet as to whether neutering is beneficial when it comes to prostate issues. 


Perianal Fistula is where the wall of the tract through which faeces passes to exit the anus, becomes covered with pussy abscesses, which is painful and requires surgery and can leave small channels behind, which are prone to infection, leading to the need for a heavy course of antibiotics (which destroy all good gut flora – if ever your dog needs antibiotics, ensure you supplement his diet with a good probiotic to help rebuild the flora in the gut wall for a healthy digestive and immune system). Neutering does reduce the risk of Perianal Fistulas, as per the previous paragraph as they’re non-cancerous. 


Hypothyroidism 

There is evidence which suggests a strong correlation between neutered dogs and hypothyroidism. Although this is not generally life threatening, bar giving a poor quality of life through obesity, it is a lifelong condition, which has to be controlled through medication, and diet. 


Weight Gain

The most common side affect of neutering at any age, happens in the vast majority of dogs – weight gain! The chance of weight gain increases by three times, due to the dog’s metabolism being affected by the lack of hormones. In some breeds it is more prevalent than others, and owners must keep an eye on their dog’s weight and adjust portions appropriately. 


Cognitive Ability in Later Years 

It is also thought that there is a link between dog ‘dementia’ and early neutering. This is another topic still under exploration. 


Hip Dysplasia and Torn Ligaments 

These two ailments are strongly linked with early neutering, due to the inability for the body to grow properly, and for growth plates to fully close. Ruptured cruciate ligaments are so common in dogs, but more so in those neutered too early. Both illnesses are extremely painful, sometimes require NSAIDs (Non-Steroidal Anti Inflammatory) daily for life, which in turn can affect kidney function. In the worst cases of torn ligaments, surgery is required. Hip dysplasia has detrimental effects to a dog’s mobility, and spinal health too. 


Behaviour

Testosterone driven behaviours

Some pros to neutering dogs are that it reduces the risk of testosterone driven behaviours. These include excessive marking (marking every time a dog is near-by), chasing and mounting females, and fighting other dogs when a bitch is present. Obviously, these are undesired behaviours for your typical pet dog, and each can be reduced (not eradicated completely) by neutering. They cannot be eradicated completely because there will still be a little testosterone in the body when the gonads are removed, and can also become ‘learnt’ behaviours which need strict one to one training to resolve (using positive only methods only). 


Unfortunately, many entire male dogs unknowingly give off signals to others due to the hormones present in their body. Some males see this as a threat, which will sometimes provoke a seemingly unprovoked attack. Neutering can reduce the risk of an attack of this manner, but equally, there are often other controls in play during these times – even something as simple as a dog having a black coat and black eyes, making it difficult for other dogs to read body language in the head. 


Dogs with low confidence levels and nervous dogs 


Many owners struggle with their dog’s reactivity to humans and/or other dogs, separation anxiety/ clinginess, guarding (particularly common in Cocker and Cavalier King Charles Spaniels amongst other breeds) of food or resources, and fear of loud noises, uncertain situations and busy places. Neutering a dog displaying any of these behaviours can be severely detrimental to its mental wellbeing. Stripping it of most of its hormones also essentially strips it of its confidence, and push it further down the ‘hierarchy’ of dogs in social situations and less confident in being left (if suffering from separation anxiety), making these behaviours more severe or harder to train out of the dog. Urine marking (not excessive) can be due to a dog not being confident too and can easily become a learnt behaviour. 


Dogs suffering with high arousal behaviours 


A high arousal behaviour is one which comes across as ‘over excitement’ – whether it be pacing, mouthing, lunging when on lead, as well as humping items around the house. It is unknown if castration fully affects these behaviours, but is being explored, and based on current available knowledge of how hormones affect behaviour and confidence levels in dogs, I recommend steering clear of castration until the dog is more settled. Many of these behaviours can easily become learnt behaviours, in which case, neutering the dog may make them harder to train out of the dog. Again, positive method bases one-to-one training is needed to work on ridding a dog of a learnt behaviour. 


But my dog’s happy and friendly! 


In my 10+ years of working with dogs and training in various aspects of animal care (non-veterinary by degree, I just enjoy researching about health and welfare with an unbiased view), I have witnessed, on numerous occasions, situations where dogs who were previously seemingly happy and confident, get neutered and fall a victim on anxious ways! An example is Butler, a large breed dog who was neutered at 6 months of age, who I walk every day. He used to be a happy go lucky, excitable dog (showing signs of high arousal judging by his owner’s description of pre neuter behaviour) – his energy is now fixated on other dogs, lunging toward them on lead, and always wanting to be the best and biggest pee dancer/scraper if in the vicinity of any other males. This shows his high arousal has become far worse than it was before. He also has some movement/gait issues at the mere age of three years old, due to growth plates not forming properly, and such a heavy weight due to his size, baring on the poorly formed joints. 


Types of neutering 

Traditional surgery 


Obviously with traditional surgery the dog goes under anaesthetic, which has its own risks associated. There is also the added risk of infection at the wound site, and internal suture haemorrhage which would require immediate veterinary attention. The recovery for this is not as long as it would be for a female spay as it is a little less invasive, but still requires a dog to rest for up to a week, more in some cases. 


Keyhole Surgery 


Although expensive, keyhole surgery requires very little recovery time. This method is generally used on females, but it is used on males in the instance the dog has a retained testicle. 


Chemical Castration 


This can be used as a way to tell what a dog would be like, minus its hormones. This is non-permanent and will wear off after 6 or 12 months depending on which drug is used. This method does come with its side-affects, and is one we wouldn’t recommend as a general rule of thumb. One chemical castration drug was released, but promptly withdrawn from the marked due to major complications in dogs given it. A second was released shortly after which was safer to use. Infertility, coat condition and obesity are amongst the most common side-affects for these drugs. There are so many potential side effects, perhaps less common, but certainly a concern, such as the increase in testosterone just after administration of the Suprelorin, hypothyroidism, and other major autoimmune conditions. we would encourage you to fully read this article by Heal The Dog. 



What to do if you neuter and find your dog’s mental wellbeing decline 


As the surgery is non reversible, further treatments would be needed for any problems which arise, health wise. Mentally however, there are things you can do. Look for a behaviourist who is qualified in Zoopharmacognosy. I can recommend a fantastic one in the Berkshire area if ever needed. We have a fabulous behaviourist on the team, specialising in pain; you can find Jamie at https://www.thespeedofhounddogtraining.com/ Working one-to- one with the dog on coping methods is essential – keep away from triggers if possible, too. There is also a hormone replacement powder which is handy to give (the brand is Dr Mercola – she’s a highly qualified holistic vet who noticed the problems associated with a lot of information given by many ‘normal’ vets and has a range of natural products to help those with the problems associated to misuse or misinformation of ‘routine’ treatments). Although this will not solve the issues entirely, it certainly helps dogs to gain a little more confidence, but as one can imagine, nothing beats the real thing! 


Undescended Testicles


Sometimes, a dog’s testicles are trapped, so don’t ‘drop’ – this is called cryptorchidism. The risk of the trapped testicle(s) becoming cancerous is much higher than in properly developed ‘dropped’ testicles. For this reason, it’s important to neuter. Most vets will advise neutering these dogs at 6 months; however, this is really not necessary and doesn’t give them a chance to descend. You have until 24 months of age before the risk increases! So, keep those balls for as long as possible! If only one testicle is trapped, you can opt to have just the stuck one removed and keep the properly formed one intact to benefit from its hormones. 


Some people have success with massaging the testes down into place, others come naturally, just a little later than expected. Homeopathy can also be used to help encourage the testicles to drop – Canine Natural Cultures offer a homeopathic remedy for this very problem and can be purchased here https://www.caninenaturalcures.co.uk/homeopathy-for-dogs/homeopathy-for-dogs/ boy-special-young-immature-male-dogsand another from HAMPL Naturopathy called U-Testes: https://holisticanimalremedies.com/product/undescended-testicles-with-your-puppy-colt-calfrabbit-all-species/ 


A Comparison


The study highlighted in the bibliography section for ‘A Comparison’ shows a clear correlation between longevity and neutering at the correct age. When personally weighing up this article with the rest of the studies I have read, if your dog shows no signs of high arousal or low confidence, I would consider neutering after 2 years of age – I would most likely leave it until 3+ years of age for larger dogs, and would not consider it until any undesired behavioural traits have been flattened out through positive reinforcement training. We recommend keeping a male entire for as long as possible unless medical intervention is required. 


Bitches, and Spaying


Spaying a bitch too early (earlier than 2 years in small to medium breeds, earlier than 3 years in giant breeds) can also have similar side effects. In entire females, the risk of pyometra is certainly something to be aware of. The risk of pyometra increases exponentially with age, but generally speaking is not much of a risk before 2-4 years of age. If you decide to spay your female wait until at least 2 years of age but do keep a look out for signs of pyometra (lethargy, lack of appetite, discharge from the vulva, extensive urination, excessive drinking, vomiting and, in the worst cases, collapsing). When spaying, its best to wait until 3 months after the end of a season. 


With an entire female in the house, I would have a phantom pregnancy first aid kit on hand. Homeopathic Pulsatilla 30c is great to help stop a phantom pregnancy in its tracks. Urtica Urens 30C can also be used. Homeopathic Sepia 30C can be used too if the female is suffering mentally (depression). To help reduce the chance of a phantom pregnancy happening on the next season, you can give raspberry leaf from day one of the next season. Some females can be a little anxious during or after their season, so Skullcap & Valerian may be handy to have on the shelf too. For girls who feel ‘low’ during their season, Evening Primrose Oil is helpful. 


Mammary infections are rare, but can happen (pus from teats, lethargy) so it’s good to keep an eye out. 


Girls who regularly struggle with phantom pregnancies are at greater risk of pyometra. Types of Spay 


Types of Spay 


Traditional spay: the ovaries and uterus are removed; this eradicates all hormones. It can be performed laparoscopically (keyhole) which will be more expensive, but a shorter recovery time. 


Ovary Sparing Spay: the uterus is removed but the ovaries are kept. The dog may still experience small, light seasons, and can be susceptible to stump pyometra (infection of the stump left after removal of the uterus). This method leaves the important hormones in the body which can be beneficial. There are not many vets who are specially trained in this technique, so will be more costly, and harder to find. 


Handy Link: NOAH Compendium – useful for looking up the manufacturer’s information sheet, for side-affects, proper dosing schedule etc of anu drug prescribed by a veterinary surgeon. https://www.noahcompendium.co.uk/home


© Written by Bethany Calhoum, NO BULL Just Natural Health for Dogs. 

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