Why should you desex your cat by four months of age?




The Cat Management Act 2009 has undergone some recent amendments and it is changing the way that cats are managed in Tasmania. One of the changes that will come into effect from 1 March 2022 is that all cats over the age of four months must be desexed. Some cat owners may have been wondering what the best age is to have their kitten desexed and whether four months is too young, as most domestic cats are currently desexed at or after six months of age.


In June 2021 RSPCA Australia published a research report looking at the potential benefits and drawbacks of desexing cats by four months of age. The report is call “Pre-pubertal desexing in cats”. In this blog we will provide a summary of their findings.


Why are we talking about desexing cats at a younger age?

The large number of unwanted cats is a big problem in Australia. Cat management facilities, shelters and pounds are often at capacity leading to concerns for the welfare of individual cats, as well as creating social and environmental issues.


In Tasmania alone, 5000-6500 cats get handed in to cat management facilities and shelters every year. The majority of cats that are surrendered are kittens that are born during ‘kitten season’, which in Tasmania can last from around October to April.


Almost 40% of kittens surrendered to RSPCA Australia are reported to be from owned domestic cats. The main reason for surrendering a litter of kittens is because people now have ‘too many cats’ or the litter was ‘unplanned’. The large number of owned kittens that are surrendered each year is a major concern.


Female cats can become pregnant as early as four months of age. Their pregnancy lasts 63 days and they can produce their first litter of kittens by six months of age. The mother cat can be sexually receptive again as soon as 7-9 days after giving birth. Male cats become sexually mature when they are a bit older, but they can sire a litter by five months of age. On average, non-desexed cats can produce 4.2 kittens per litter and 2.1 litters per year. This means that cats can multiply very rapidly.


Desexing cats before they are able to reproduce can significantly reduce the overpopulation of owned domestic cats.


Studies have shown that 83-97% of the owned domestic cats in Australia are desexed. So why are we still seeing such a high number of owned kittens surrendered to facilities and shelters every year? One possible explanation is that cats are producing an unplanned litter of kittens before they are desexed. Remembering that cats can become sexually active from 4-5 months of age, studies have found that only 23-33% of cats under six months of age are desexed. While these studies show that most cat owners are very diligent and have their cats desexed, the studies also show that cats are being desexed too late in life to prevent unwanted litters. This is why Tasmania has changed their legislation and is now making it mandatory to have your cat desexed by four months of age.





What is pre-pubertal desexing?

Pre-pubertal desexing simply means desexing before puberty. It refers to desexing a cat at or before four months of age, before cats are physically capable of reproducing. In most cases pre-pubertal desexing is performed between 12-16 weeks of age.

Currently, most domestic cats are desexed at or after six months of age, but pre-pubertal desexing is already routinely done by cat management facilities, breeders and shelters.


The benefits of pre-pubertal desexing

Desexing cats before puberty prevents unplanned litters of kittens and will assist in reducing the overpopulation of both domestic and stray cats in Australia. But there are other benefits to desexing a cat before puberty as well. Many studies have compared the medical and behavioural outcomes of pre-pubertal desexing to those of desexing at the more traditional age of six months or older. They have found that pre-pubertal desexing has:

  • Shorter surgical times for both males and females. This means that the cat spends less time under anaesthesia and has a smaller chance of wound infection.

  • Improved surgical outcomes, including minimal tissue trauma and a quicker recovery time, which may result in less pain after the surgery.

  • A lower overall complication rate.

  • No increased mortality rate compared to desexing at six months of age or older.

  • Not resulted in any behavioural issues. Desexing at any age will help reduce the behaviours shown by non-desexed cats that people find undesirable (such as spraying and fighting).

These studies also found no evidence of long-term health implications associated with the age of desexing.


The RSPCA report shows that desexing a cat before four months of age is a safe practice and can have significant welfare benefits for the cat. Desexing before four months of age will also reduce the number of unwanted kittens in the population because cats will be desexed before they can physically reproduce.


For more information download the full RSPCA research report: Pre-pubertal desexing in cats.