Desexing - Why?

Deciding on whether to desex your pet or not can sometimes be a tough decision, especially if you haven’t had much time to have a good think about both sides of the argument. This is why we have put together a fact sheet that explains why we believe your pet should be desexed and also aims to dispel a few common myths about the procedure.


First and foremost, desexing saves you money! Desexing your pet before the age of 6 months will save you $110 when you register your pet with the council in NSW, which by law must be done before the age of 6 months.


Desexing prevents unwanted pregnancy Unwanted pregnancy is very common in un-desexed females, even in those that are kept isolated (e.g. locked in your yard). This is because when females are on heat they are more likely to try and escape to look for a mate.

They are also more much more attractive to males who will do almost anything to get to her, including jumping 2m high fences and chewing through wire cages. Note that we can still desex your pet if you suspect that she is pregnant, but the cost of the surgery will be higher.

Desexing stops females coming into ‘heat’

Coming into ‘heat’ or ‘season’ can sometimes be a huge inconvenience for owners. Twice a year your female dog will have a bloody vaginal discharge for about 2-3 weeks at a time, which generally results in her being banished outside where she won’t make a mess. Needless to say, she will also need to be kept away from any un-desexed male, preferably in a secure enclosure that will stop her from escaping and keep males out.

Female cats will come into season every 3 weeks for the entire breeding season (usually July to March), during which time they wail, howl and behave strangely until they are mated.

Note that the cost of desexing will be increased if your pet is in season at the time of surgery.

Desexing eliminates the risk of pyometra

Pyometra is a potentially life-threatening build-up of pus in the uterus. It is very common and occurs in about 25% of un-desexed female dogs during their lifetime, and less commonly in cats.

Treatment can be expensive and risky, as surgical removal of the infected uterus is usually required. As the desexing procedure removes the uterus, this condition cannot occur in desexed females.

Desexing greatly reduces the risk of mammary (breast) cancer. 

Desexing a female before she has her first season will reduce the chance of developing breast cancer in later life by up to 99%. The more seasons she is allowed to have before she is desexed, the greater the risk of this type of cancer occurring. If a female is allowed to have just one heat her chances of developing breast cancer later in life increases from less than 1% up to 8% after her first heat, and a whopping 26% by her second heat.

Desexing eliminates phantom pregnancies

Phantom pregnancies can occur in some un-desexed females, which can be very distressing for both the animal and the owner. This does not occur in desexed females.

Other benefits

Desexing greatly reduces the risk of mastitis (breast infections) and eliminates the risk of ovarian cysts and cancer. As a secondary effect, desexing also reduces the risk of your pet contracting infectious diseases as a result of fighting, roaming and coming into contact with other animals.


Desexing reduces urine marking In many cases, desexing can control spraying in cats and urine marking in dogs, especially if performed preventatively. Un-desexed cat urine in particular has a very pungent smell.

Desexing eliminates the risk of testicular disease

As desexing involves the removal of the testicles, the chances of developing testicular cancer, cysts and infections in later life are completely eliminated.

Desexing greatly reduces the risk of prostate problems

Benign prostatic enlargement is very common in un-desexed male dogs and can cause problems with urination, constipation and predispose to prostate infections and cancer.

Desexing greatly reduces the risk of cancer around the anus and rump

Certain types of cancers in male dogs are stimulated by the hormone testosterone, the levels in the blood of which are greatly reduced after desexing.

Desexing reduces roaming and fighting

Un-desexed dogs and cats are much more likely to roam to look for a mate and challenge other animal’s territories. This presents an increased risk of being hit by a car, getting into fights with other animals and becoming a great nuisance to neighbours. Legally the owner of an unleashed animal is responsible for any associated damages caused by their pet, including car accidents and council fines.

Desexing can reduce unwanted behaviour and improve trainability

Mounting, urine marking, hyperactivity and aggression have been shown to be linked with high testosterone levels in animals.

One of the first things that animal behaviourists and trainers recommend when dealing with such behaviour problems is that the animal be desexed as soon as possible. The chance of success is markedly improved if the procedure is performed before problem arises, or if the opportunity has been missed, as soon as possible after you notice the problem.


Desexing will change my pet’s personality

Your pet’s personality is shaped by a multitude of factors, not just by their reproductive system and hormones. The animal you know and love has mainly been shaped by its previous experiences, surrounding environment, training and their overall physical health.

In fact, desexing has been shown to improve a pet’s personality by reducing unwanted behaviours such as mounting, urine marking, hyperactivity and aggression (as outlined above).

Desexing will make my pet fat and lazy

Your pet’s metabolism will slow to some extent after desexing. As a result, they will require less calories than they would have if they were left un-desexed, so will gain weight if this is not taken into account.

This is the main reason why we usually ask you to change your pet’s diet from a puppy to an adult formulation after desexing (note that this is postponed in larger breeds which continue to grow for longer).

It’s better to let her have one season first.

This is absolutely not true. In fact, allowing a female to have one season before being desexed can be potentially harmful to her health in the future. As mentioned above, if a female is allowed to have just one heat her chances of developing breast cancer later in life increases from less than 1% up to 8% after her first heat, and a whopping 26% by her second heat.

Desexing is unnatural and will sexually deprive my pet

We need to remember that our pets cannot always be directly compared to their wild counterparts. 

Pet dogs and cats have been bred over thousands of years to suit our lifestyle, which means that their needs are very different to how they used to be.

There is also no evidence to suggest that animals feel deprived or even notice that they have had their reproductive organs removed. In fact, it can be argued that an un-desexed animal would feel more sexually deprived than a desexed animal, as their hormones are functioning despite the animal not being allowed to act on their impulses.

Desexing will make my pet incontinent

While this is to some degree true, it can easily be argued that the risks of this occurring far outweighs the benefits brought on by desexing, as outlined above. Desexing has been linked to urethral sphincter incontinence in older female dogs, however can be controlled relatively easily with medication.

It’s better to let her have one litter first

While it can be a rewarding experience observing the entire reproductive process from mating through to weaning, you need to be aware that breeding you pet is not as easy as it sounds. Just like with humans, many things can go wrong during a pregnancy that not only risk the life of the mother and babies, but also can involve significant costs for you as the owner.

For example, if required, an emergency caesarean section can cost anywhere between $1000 and $2000 depending on the breed, age, health status, any complications involved, and whether the procedure is performed outside clinic hours. Add on the cost of regular check-ups before, during and after the pregnancy, the treatment of any complications such as hypocalcaemia (milk fever), hand-rearing the litter if they are rejected, the cost of micro-chipping the entire litter (compulsory by law), first vaccinations and worming, and you can end up with a considerable bill by the end of it all.

Another thing to consider when it comes to breeding is the ethics of bringing more puppies and kittens into this world.

Every year hundreds of thousands of animals are euthanaised at pounds, shelters and veterinary clinics simply because there are not enough homes for them to go to. So please have a long think about whether you think that creating more of these animals is the right thing to do.

If you do end up deciding to breed from your pet, please discuss this with one of our staff members who can give you some more specific advice before going ahead.

We can give you advice on mating, pregnancy diagnosis, diet modification, the birthing process, hand-rearing techniques and weaning tips.