Cat neutering is one of the most common procedures in veterinary medicine — and one of the most debated among pet owners. When should it be done? Is it expensive? Does it change a cat's personality? In this guide we answer all your questions, drawing on the latest ISFM (International Society of Feline Medicine) guidelines.

Spaying vs neutering: what's the difference?

  • Spaying (female): removal of the ovaries and/or uterus (ovariectomy or ovariohysterectomy)
  • Neutering (male): removal of the testicles

In everyday language, "neutering" is commonly used for both sexes.

What age should you neuter your cat?

International guidelines (ISFM, AAFP, AVMA) recommend early neutering, around 4–5 months of age. Traditionally, 6–8 months was the norm, but we now know that early neutering:

  • is safer (less fatty tissue, faster recovery)
  • prevents the first unwanted litter
  • reduces the risk of mammary tumours by more than 90%

The 5 real benefits

For females

  • Elimination of pyometra risk (a life-threatening uterine infection that affects 1 in 4 unspayed females)
  • Dramatic reduction in mammary tumours (90%+ if done before the first heat cycle)
  • No more heat cycles: no night-time vocalising, restlessness or urine marking

For males

  • Fewer escapes and road accidents (an intact male can roam up to 5 km a day in search of a female)
  • Dramatic reduction in urine marking and territorial fighting
  • Lower risk of FIV/FeLV: these viral diseases are transmitted through fights

Typical costs

  • Male neutering: €80–150
  • Female spaying: €150–280
  • Pre-anaesthetic tests (blood work, ECG): €50–100

Many local health authorities offer subsidised schemes at reduced rates, especially for feral colony cats. Check with your local council or the LNDC.

How to prepare for the procedure

The day before

  • No food from 10 pm the previous evening
  • Water available until the morning
  • Pre-operative tests if requested by your vet

On the day of the procedure

  • Transport in a sturdy carrier (not an open backpack)
  • A familiar blanket carrying their scent
  • Same-day collection — your cat will be awake but drowsy

Post-operative care: 7 days of close attention

First 24 hours

  • Keep your cat warm, in a quiet room
  • Offer water straight away; food after 3–4 hours (reduced portion)
  • Prevent jumping on furniture: risk of tearing the stitches
  • Elizabethan collar or surgical bodysuit to stop them licking the wound

Days 2–7

  • Check the wound daily: it should be dry, free of pus, and show no spreading redness
  • Reduced activity: no jumping, no going outside
  • Stitches removed by the vet between day 7 and day 10 (if non-absorbable)

When to call the vet

  • Bleeding from the wound
  • Persistent vomiting
  • Loss of appetite beyond 36 hours
  • Fever or profound lethargy
  • Swelling or discharge from the wound

After neutering: will your cat change?

What really does change

  • Metabolism: slows by 20–30%, so your cat will tend to gain weight if their diet isn't adjusted
  • Calmness: less restlessness, no more heat cycles or marking behaviour
  • Affection: often increases — they tend to become more of a homebody

What does NOT change

  • Personality: a playful cat stays playful, a shy cat stays shy
  • Intelligence: zero impact
  • Core habits (favourite napping spot, preferred food, etc.)

Feeding your neutered cat

After neutering, calorie requirements drop by 20–30%. You'll need dry or wet food specifically formulated for neutered cats, with:

  • High protein content (≥35% dry matter)
  • Reduced fat content (8–12%)
  • L-carnitine (supports fat metabolism)
  • Controlled magnesium and ash levels (reduces the risk of struvite)

Weigh out their portions: free-feeding dry food left in the bowl at all times is the number-one cause of obesity in neutered cats. 40% of neutered cats are overweight.

Frequently asked questions

Is it better to wait for the first heat cycle?

No. In fact, each heat cycle increases the risk of mammary tumours. Early neutering is now recommended by all international guidelines.

My cat lives entirely indoors — do I still need to neuter them?

Yes. The health benefits (no pyometra, reduced tumour risk) are independent of outdoor access. What's more, heat cycles in females are very stressful, even for cats that never mate.

Can the procedure be performed on a cat in heat?

Technically yes, but the risk of bleeding is higher. It is better to wait until the heat cycle ends (5–7 days afterwards).

How long does a neutered cat live on average?

Recent studies show that neutered cats live an average of 2–3 years longer than unneutered ones, largely due to a reduced risk of disease and accidents.

If you've just had your cat neutered, be sure to read our guides on adapting the diet for senior cats and on managing your feline's weight.