Health & Medical

Almost every pet owner faces this decision within the first year, usually while holding a leaflet from the vet and feeling vaguely uneasy about it. The surgery is routine. That does not make it trivial, and it deserves a proper explanation rather than a shrug and a booking form.

What the operations involve

Neutering a male, technically castration, removes both testicles through a small incision. In dogs the incision sits just in front of the scrotum; in cats it is made in the scrotum itself and usually needs no stitches at all. It is quick, typically fifteen to twenty minutes of surgical time, and recovery is fast.

Spaying a female is more involved because it is abdominal surgery. The traditional approach, ovariohysterectomy, removes the ovaries and uterus through an incision in the belly. An increasingly common alternative, ovariectomy, removes only the ovaries through a smaller incision, and outcomes are comparable. Some practices offer laparoscopic spays through two or three tiny keyhole incisions, which reduces pain and speeds recovery, at higher cost.

Both are done under general anaesthesia with pre-operative checks. Most clinics run bloodwork beforehand to check liver and kidney function, place an intravenous catheter, and monitor blood pressure, oxygen and heart rhythm throughout. Anaesthetic risk in a healthy young animal is genuinely low, though never zero, and it is reasonable to ask your clinic what monitoring they provide.

The timing question, which has genuinely changed

For decades the standard advice was six months for everything. That advice has shifted, particularly for dogs, and it is now more nuanced.

Cats are straightforward. Neutering from around four to five months, before sexual maturity, is standard and well supported. Female cats can get pregnant surprisingly young, and early neutering prevents that along with spraying, roaming and fighting in males.

Dogs are where the conversation gets interesting. Sex hormones contribute to the closing of growth plates, so desexing a large-breed dog very early can result in slightly longer limbs and altered joint angles. Research over the past decade has linked early neutering in some large and giant breeds with higher rates of cruciate ligament rupture, hip dysplasia and certain cancers.

The practical result is a size-based approach. Small dogs under about 10 kilograms are generally fine from six months, since they finish growing early. Medium dogs are often done between nine and twelve months. Large and giant breeds are increasingly left until twelve to eighteen months, or after the first season in females, to allow skeletal maturity.

Against that, waiting has costs. Each season a female goes through raises her lifetime mammary tumour risk, and spaying before the first season reduces that risk dramatically. There is no universally correct answer, which is why this should be a conversation about your specific dog, its breed, sex and household, rather than a rule applied blindly.

The benefits that are not in dispute

For females, spaying eliminates pyometra, a uterine infection that is common in unspayed older bitches and is genuinely life-threatening, often requiring emergency surgery in a sick animal. It removes the risk of ovarian and uterine cancer, prevents seasons with the associated bleeding and male attention, and substantially reduces mammary cancer risk when done early.

For males, neutering eliminates testicular cancer and reduces prostate enlargement and perineal hernias. It reduces roaming, which in practice reduces road traffic accidents, fights and lost pets. Urine marking and mounting often improve, though behaviour that has become habitual may persist.

Neither operation reliably fixes aggression or anxiety. In fact, evidence suggests neutering a fearful male dog can occasionally make anxiety worse, because testosterone contributes to confidence. Behaviour problems need behaviour work.

Recovery, and the fortnight that follows

Most pets come home the same day, groggy and a little wobbly. That evening they may be quiet, uninterested in food or slightly nauseous from the anaesthetic. Offer a small light meal and plenty of water.

Pain relief is not optional. Your vet should send you home with several days of anti-inflammatory medication, and you should give it as directed rather than deciding the animal looks fine. Animals mask pain, and controlled pain heals faster. Never give human painkillers; paracetamol is fatal to cats and ibuprofen causes ulcers and kidney damage in both species.

The incision needs to stay dry and untouched for ten to fourteen days. That means no bathing, no swimming, and no licking. A cone is the reliable solution, and although everyone hates them, a surgical recovery suit is a decent alternative for many pets. A single determined licking session can open a wound and turn a simple recovery into a second surgery.

Restrict activity for the full recovery period. Lead walks only for dogs, no jumping on and off furniture, no stairs where avoidable, and no rough play. Cats should stay indoors entirely. This is hardest around day four or five, when the animal feels well and the tissue underneath is still weak, and it is exactly when most complications happen.

Check the incision twice daily. Mild redness and slight swelling are normal. Call your vet for significant swelling, discharge, a wound that opens, a bad smell, ongoing lethargy after 48 hours, vomiting, or refusal to eat for more than a day.

Weight, the one real long-term side effect

Metabolic rate drops after desexing, often by twenty to thirty percent, while appetite frequently increases. Feed the same amount as before and your pet will gain weight steadily and silently.

The fix is simple and needs to start immediately, not after the pet is overweight. Reduce food by roughly a fifth to a quarter about two weeks after surgery, monitor body condition monthly by feeling ribs and looking for a waist, and adjust from there. Desexed pets are not doomed to be fat; they are just fed by owners who did not adjust the portions.

Beyond that, expect the same animal you had before. Slightly calmer in some cases, less driven by hormones, and statistically likely to live longer. For most households, that is a good trade.