Most people start looking into spaying or neutering when a puppy or kitten is growing fast, a first heat is looming, or an escape has already happened. The decision can feel simple until you start hearing conflicting advice about timing, behaviour changes, and long-term health.
Spaying (for females) and neutering (for males) are routine veterinary surgeries, but they’re still real operations with real aftercare. The best choice depends on species, sex, breed, and how your animal lives day to day. The aim here is to keep it grounded: what the procedures are, what they prevent, what they don’t, and how to pick a sensible time with your vet.
What “spaying” and “neutering” actually mean
Spaying (female animals)
Spaying usually means removing both ovaries and the uterus (ovariohysterectomy). It prevents pregnancy and stops heat cycles. It also removes the organ that can develop pyometra, a serious uterine infection that can progress quickly and may be fatal without treatment.6
Neutering (male animals)
Neutering typically means removing both testicles (castration). It prevents reproduction and eliminates the risk of testicular cancer. It can also reduce some hormone-driven behaviours, though training and environment still matter.
Why desexing matters (and what it can realistically change)
Health benefits you can point to
- Prevents pyometra in females by removing the uterus and hormone-driven cycling that sets up the infection.6
- Reduces mammary tumour risk in females when done early, especially before the first heat. In cats, most mammary tumours are malignant, and early spaying is strongly protective.7
A common claim is that “breast cancer is fatal in 50% of dogs and 90% of cats”. The reality is more specific: in cats, around 80–90% of mammary tumours are malignant; in dogs, roughly half are malignant.7, 8 What matters for owners is that mammary disease can be aggressive (especially in cats) and spaying early reduces risk.7, 8
Behaviour changes: what’s likely, what’s not
Desexing can reduce behaviours closely tied to reproductive hormones, such as roaming to find a mate and some urine-marking. It does not erase learned habits, fearfulness, poor socialisation, or boredom. Those tend to shift with training, enrichment, and routine, not surgery alone.
For female animals, spaying stops heat cycles, which means you won’t see the heat-related behaviours and attraction from males.
Population control and shelter pressure
Accidental breeding can start earlier than many people expect. Cats can breed from around four months of age, so “waiting until later” can quietly become “already happened”.2, 3 Early desexing is one of the practical tools used to reduce unwanted litters and the flow of animals into shelters.2
Timing: when to desex (and why advice varies)
There isn’t one perfect age for every pet. Timing is a balance between:
- preventing an early, unplanned pregnancy (especially in cats),
- your pet’s size, breed, and growth pattern,
- your ability to prevent roaming and mating,
- any medical risks your vet identifies at a pre-anaesthetic check.
Cats: often earlier than people think
In Victoria, Animal Welfare guidance notes that desexing is a routine surgery that can be done for cats from around 2–3 months (and other guidance commonly recommends before puberty).1, 5 That early timing is largely about biology: cats can become fertile at roughly four months.2
Dogs: more individual, especially for large breeds
Many vets still commonly desex dogs around six months, but the “best” time can shift with breed, body size, and orthopaedic history. Some organisations and clinics note that later desexing may be recommended for some larger-breed dogs, so it’s worth making this a deliberate conversation rather than a default booking.3
What the surgery day usually looks like
Before
Your vet will usually do a physical exam and may recommend pre-anaesthetic blood tests. You’ll be asked to fast your pet beforehand (your clinic will give exact instructions).
During
Both procedures are performed under general anaesthesia with pain relief. Spays generally take longer than neuters because they involve abdominal surgery.
After
Most pets go home the same day. Expect sleepiness that night. The first week is mostly about keeping movement calm while the incision seals.
Recovery and aftercare: small details that prevent big problems
- Keep activity low for the period your vet recommends (often around 10–14 days for a spay).
- Stop licking with an e-collar or recovery suit if your pet worries at the wound.
- Check the incision daily for swelling, heat, discharge, gaping, or a bad smell.
- Call your vet promptly if your pet won’t eat, seems unusually lethargic after the first day, is vomiting, or the wound looks worse rather than better.
Myths that keep circulating
“It changes their personality”
Desexing doesn’t rewrite who an animal is. It can reduce some hormone-driven behaviours, but temperament is also shaped by genetics, learning, and the home environment.
“A female should have one litter first”
There’s no health requirement for a first litter. If anything, delaying spaying increases the window for accidental pregnancy and increases lifetime exposure to reproductive hormones linked with mammary disease risk.7, 8
Risks and how vets manage them
Any anaesthetic and surgery carries risk, but desexing is a routine procedure in general practice. Risk is managed through pre-anaesthetic assessment, careful monitoring under anaesthesia, sterile technique, and effective pain control, plus clear aftercare instructions.
The biggest preventable post-op issues are usually behavioural rather than medical: too much running and jumping too soon, or persistent licking that breaks down the incision.
Legal and cultural notes in Australia
Desexing rules vary by state and local council. For example, some jurisdictions have cat desexing requirements, and some councils use registration rules or fees to encourage desexing. If you’re unsure, check your council’s pet registration page and your state’s current guidance.4
Cost and access
Pricing varies by clinic, species, sex, size, and whether your pet needs additional care (such as cryptorchid surgery for a male dog with an undescended testicle). If cost is the barrier, ask your local council about assistance programs and discounts, and check for community desexing programs in your area.2, 5
Alternatives (and why they’re not the usual first choice)
There are non-surgical options in some situations (for example, hormone-based control in females, or vasectomy in males). These approaches can be more complex to manage, may not provide the same health protections as spaying, and some hormonal methods can carry meaningful side effects and risks. If you’re considering alternatives, treat it as a vet-guided plan rather than an “off the shelf” fix.9
Final thoughts
Desexing is one of those quiet, practical interventions that changes the shape of a pet’s whole life: fewer medical emergencies, fewer accidental litters, fewer high-stakes decisions made in a rush. The best timing is the one that fits your animal’s biology and your real-world ability to prevent mating, agreed on with a vet who knows your pet.
References
- Animal Welfare Victoria — Early age desexing (cats)
- Animal Welfare Victoria — Desexing cats and dogs
- RSPCA WA — What age does a cat/dog need to be before they can be sterilised?
- RSPCA Knowledgebase — Is desexing mandatory for cats and dogs? (legislation summary)
- RSPCA Victoria — Desexing and breeding pets
- Merck Veterinary Manual (Dog Owners) — Reproductive disorders of female dogs (pyometra)
- Merck Veterinary Manual (Professional) — Mammary tumors in cats
- Merck Veterinary Manual (Dog Owners) — Mammary (breast) tumors in dogs
- Merck Veterinary Manual — Prevention or termination of pregnancy in dogs and cats
Veterinary Advisor, Veterinarian London Area, United Kingdom