Vet nurse’s guide to desexing your pet

Should I desex my dog or cat? A practical guide for pet owners.

Desexing, also known as neutering, is a common and highly recommended procedure in veterinary medicine. As veterinary nurses, we often speak with pet owners about the timing, benefits, risks, and recovery involved. Whether you’re a first-time pet owner or considering breeding, it’s essential to understand what desexing entails and how to care for your pet before and after surgery.

What is desexing?

Desexing refers to the surgical procedure that removes an animal’s reproductive organs, making them unable to breed.

• Spey (female): the uterus and ovaries are removed under general anaesthesia through an abdominal incision. This eliminates the possibility of pregnancy and heat (oestrus) in females.
• Castration (male): the testicles are removed under general anaesthesia through a small incision near the scrotum. This stops sperm production and significantly reduces testosterone levels.

Both procedures are performed under general anaesthesia in a sterile veterinary surgical theatre.

Sexual maturity and oestrus (heat) cycles

Understanding when your pet becomes sexually mature helps you make informed decisions about desexing timing.

Dogs

• Sexual maturity usually occurs between 6–12 months, depending on the breed and size. Smaller breeds mature earlier; large breeds take longer.
• Oestrus (heat) in females generally begins between 6–10 months. Most female dogs come into season every 6–8 months.
• Signs of oestrus include swollen vulva, blood-tinged vaginal discharge, increased urination, attraction of male dogs, and behavioural changes like restlessness or clinginess.
• The heat cycle lasts about 21 days, and during this time, females can become pregnant.

Cats

• Sexual maturity can occur as early as 4 months of age for females. Male kittens reach sexual maturity around 7-8 months of age.
• Female cats, known as queens, typically come into heat every 2–3 weeks during the breeding season, which runs from spring through early autumn. They are seasonally polyoestrous, meaning they can have multiple heat cycles in that period. Ovulation is triggered by mating.
• Signs of oestrus include loud vocalisation (calling), rolling and rubbing, affectionate behaviour, and attempts to escape outdoors.
• Cats do not have vaginal bleeding, and heat can last several days to a week, recurring every few weeks if they are not mated.

Males (dogs and cats)

Male dogs and cats can become sexually mature around 5–6 months. Un-neutered males may show behaviours like marking, mounting, roaming, and fighting with other males.

When should pets be desexed?

Dogs

• Small to medium breeds (under 20 kg) are typically desexed around 5–6 months of age.
• Large and giant breeds may benefit from delayed desexing (after 12–18 months) to support joint development.

Cats

Desexing is recommended between 4–6 months of age. Some shelters and clinics offer early-age desexing (as early as 8–10 weeks) to help control overpopulation.

Desexing and pet registration in Australia

Across most Australian states and territories, desexing is linked to pet registration laws.

• In New South Wales, dogs and cats must be lifetime registered by 6 months of age. Discounted registration applies for desexed pets.
• In Victoria, registration fees are lower for desexed pets, and councils encourage desexing from 3–6 months.
• In South Australia, dogs must be desexed by 6 months of age unless an exemption applies.
• In the ACT, cats must be desexed by 3 months and dogs by 6 months unless exempt.

Delaying desexing for health reasons

If your vet recommends delaying desexing for a large breed dog, they can provide a written exemption letter for council registration. Speak to your vet or vet nurse to arrange this during your consult.

Benefits of desexing

Health benefits:

• Prevents uterine infections (pyometra) and reproductive cancers
• Reduces the risk of mammary tumours, especially if desexed before the first heat
• Prevents testicular cancer and lowers the risk of prostate disease

Behavioural benefits:

• Reduces roaming, marking, and aggression
• Prevents female oestrus behaviours and unwanted male attention
• Helps calm hormone-driven behaviours in both sexes

Community and environmental benefits:

• Prevents unwanted litters
• Reduces stray populations and shelter overcrowding
• Protects native wildlife from predation, especially by cats

Post-surgical recovery at home

Your veterinary team will provide specific aftercare instructions, but general guidelines include:

1. Rest and restriction: Keep your pet calm and indoors for 7–10 days. Avoid off-lead walks, stairs, or rough play.
2. Monitor the incision: Check daily for swelling, redness, discharge, or opening. Use an Elizabethan collar or recovery suit to prevent licking.
3. Feeding: Offer a half sized meal the evening after surgery. Appetite may be reduced for 24 hours.
4. Pain management: Give any prescribed pain relief exactly as directed. Never give human medications.
5. Suture management: Generally the stitches used for your pets procedure will dissolve. if non-absorbable sutures are used they will require removal at a 10–14 day post-op check.

Complications of not desexing

Undesexed pets are at increased risk of:

• Pyometra (a life-threatening infection of the uterus)
• Mammary cancer in females
• Testicular cancer and prostate issues in males
• Aggression, marking, and wandering behaviours
• Unplanned pregnancies and complications during birth

Risks of early desexing

Early-age desexing is safe for most pets, but some risks may apply, particularly in large breed dogs. These can include:

• Joint disorders or growth plate delays
• Urinary incontinence (mainly in females)
• Slight increase in some cancer risks in specific breeds

Your vet can help weigh the benefits and risks for your pet’s breed, age, and lifestyle.

Thinking about breeding?

Responsible breeding involves more than simply avoiding desexing:

• Only breed healthy animals with stable temperaments
• Complete appropriate health screenings (hip/elbow scoring, genetic tests)
• Be prepared for labour complications, especially in flat-faced breeds
• Have an emergency plan and vet contact in case of a difficult birth (dystocia)
• The gestation period for both dogs and cats is 63 days (+ / – 3 days)

Possible signs of birthing complications:

If your pet is in labour, contact a vet urgently if you notice:

• Strong pushing or straining for over 30 minutes without delivering a puppy or kitten
• More than 2 hours between delivering each baby
• Green, black, or foul-smelling vaginal discharge before any puppies or kittens are born
• Visible part of a puppy/kitten stuck in the birth canal
• Weak, unproductive contractions lasting over 4 hours
• The mother is exhausted, distressed, or seems unwell

Prompt veterinary attention is vital to avoid life-threatening outcomes for both mother and babies.

If you’re unsure whether labour is progressing normally, always call your vet or nearest emergency hospital for advice.

Final thoughts

Desexing is an important step in responsible pet ownership. It prevents serious health issues, reduces unwanted litters, and supports calmer behaviour.

As vet nurses, we’re here to guide you through your pet’s health journey. We’re happy to answer questions, book surgery, or help with registration paperwork and exemption letters if needed.

Need help registering your pet or getting a desexing exemption letter?
Contact your local veterinary clinic today, we’re here to support you and your furry friend.

IMPORTANT: The information in the article is not intended to be used as a substitute for veterinary advice, medical advice, diagnosis or treatment. The information provided on the website is for educational and informational purposes only. Please always seek medical treatment from a veterinarian if you have concerns about your pet’s health.