Spaying & Neutering Your Pet: When, Why, and What to Expect

Beyond preventing unwanted litters, spaying and neutering offer significant health benefits that can extend your pet's life by years.

For females (spaying):

• Eliminates the risk of pyometra — a life-threatening uterine infection affecting up to 25% of unspayed dogs
• Dramatically reduces mammary cancer risk (nearly zero if spayed before first heat)
• Eliminates ovarian and uterine cancer risk

For males (neutering):

• Eliminates testicular cancer risk
• Reduces prostate problems (benign hyperplasia affects 80% of intact male dogs over 5)
• Reduces roaming behaviour — intact males will travel miles to find a female in heat, risking traffic accidents

"Pyometra alone justifies spaying. I've performed emergency surgery on dogs whose uterus had filled with a litre of pus. It's a £2,000-3,000 emergency that a £200 elective spay prevents entirely." — Dr. Sarah Chen, DVM

Cats

The consensus is clear: 4–5 months of age for both male and female cats. Cats can become pregnant as young as 4 months, and intact males spray pungent urine to mark territory. Early neutering prevents these issues before they start.

Dogs — Small to Medium Breeds (under 20kg adult weight)

• Females: Before the first heat (around 5–6 months) for maximum mammary cancer protection
• Males: 6–9 months

Dogs — Large and Giant Breeds (over 20kg adult weight)

• Recent research suggests delaying until 12–18 months for large breeds
• Reason: sex hormones help close growth plates and develop joints properly. Early neutering in large breeds may increase risk of certain orthopaedic conditions (cruciate ligament disease, hip dysplasia)
• Discuss breed-specific timing with your vet

For the full picture of what happens at each age, see our preventive care schedule.

Spaying (Ovariohysterectomy)

Removal of both ovaries and the uterus through an abdominal incision. It's a routine procedure performed under general anaesthesia, typically taking 30–60 minutes. Laparoscopic (keyhole) spaying is increasingly available and offers smaller incisions and faster recovery.

Neutering (Castration)

Removal of both testicles through a small incision. A simpler procedure than spaying, usually taking 15–30 minutes. Recovery is generally quicker.

What to Expect on the Day

• No food from the evening before (water usually OK until morning)
• Drop-off in the morning, pick-up the same afternoon or evening
• Your pet will be groggy from anaesthesia — this is normal
• You'll receive pain medication and aftercare instructions
• A buster collar (cone) or surgical suit to prevent licking the wound

Costs vary — see our budgeting guide for typical prices. Many rescue organisations offer subsidised neutering.

First 24 Hours

• Keep them warm, quiet, and calm
• Offer a small meal in the evening (they may not eat — that's normal)
• Check the incision site — it should be clean with no excessive swelling
• Carry cats; lead-walk dogs to the garden for toilet breaks only

Days 2–10

• Restrict activity — no running, jumping, climbing stairs, or rough play
• Keep the cone/suit on at all times — licking causes infection and dehiscence (wound opening)
• Give all prescribed pain medication on schedule
• Check the wound daily: mild redness is OK; pus, swelling, or opening is not

Day 10–14

• Stitches removed (or dissolve on their own if dissolvable sutures used)
• Post-op check with your vet
• Gradual return to normal activity over the following week

Call your vet if: the wound opens, discharge appears, your pet refuses food for more than 24 hours, or they seem excessively painful despite medication.

• "My pet will get fat." — Neutering reduces metabolic rate by about 20%. This means you need to reduce food portions accordingly, not skip neutering. See our weight management guide
• "She should have one litter first." — There is zero medical evidence for this. In fact, spaying before the first heat provides the strongest cancer protection
• "It changes their personality." — Neutering reduces hormonally-driven behaviours (roaming, mounting, urine marking, inter-male aggression) but does not change your pet's fundamental personality
• "It's too expensive." — A routine spay costs £150–£300 (UK) or $200–$500 (US). Emergency pyometra surgery costs £2,000–£4,000. Mammary cancer treatment: £3,000+
• "Only females need it." — Males benefit too: no testicular cancer, fewer prostate issues, reduced aggression and roaming, and no contributing to unwanted litters