Getting neutered means surgically removing an animal’s testicles to permanently prevent reproduction. The term technically applies to sterilizing any pet regardless of sex, but in everyday use, “neutering” almost always refers to the procedure on males. For females, the equivalent surgery is called spaying, which removes the ovaries and uterus. Neutering is one of the most common veterinary surgeries performed worldwide.
What Happens During the Surgery
The veterinarian makes a small incision, typically in front of or on the scrotum, then pushes each testicle through the opening. The blood vessels and cord attached to each testicle are tied off and the testicles are removed. The whole procedure is done under general anesthesia, and most pets are in and out of the clinic the same day.
There are slight variations in technique depending on the species, the size of the animal, and your vet’s preference. In cats, the incision is usually made directly on the scrotum. In dogs, it’s often made just in front of it. Either way, the result is the same: both testicles are removed, which stops the production of sperm and nearly all testosterone.
Why Owners Choose to Neuter
The most obvious reason is preventing unwanted litters. But removing the testicles also eliminates or reduces several health risks. Roughly 1 in 3 intact male dogs will develop a testicular tumor in their lifetime. Neutering removes that possibility entirely. It also prevents a condition called prostatic hyperplasia, where the prostate gland swells due to ongoing testosterone exposure, which can cause discomfort and urinary problems as a dog ages.
Behavior is the other major factor. Intact males are more likely to roam, urine-mark inside the house, and show aggression toward other males. Neutering significantly reduces these behaviors in most animals, especially if performed before the behaviors become deeply ingrained habits.
How It Affects Weight and Metabolism
Neutering changes your pet’s metabolism. In cats, studies show daily energy requirements drop by 24 to 33 percent after the surgery compared to intact cats. Dogs experience a similar, though slightly less dramatic, metabolic slowdown. This means a neutered pet eating the same amount of food as before will gain weight.
The fix is straightforward: reduce portion sizes after the surgery and monitor your pet’s body condition over the following months. Most vets will recommend switching to a food formulated for neutered pets or simply feeding about 20 to 30 percent less. Weight gain after neutering isn’t inevitable. It just requires an adjustment that many owners don’t realize they need to make.
When to Neuter Based on Breed and Size
Timing matters more than many people realize, and the old advice of “six months for everyone” has been replaced by breed-specific guidelines. A large study covering 35 dog breeds found that neutering too early can increase the risk of joint disorders and certain cancers in some breeds, while in others, the timing makes little difference.
For small breeds like Chihuahuas, Maltese, Pugs, Pomeranians, and Dachshunds, there’s no elevated risk from early neutering, so the timing is flexible. Medium breeds vary: Beagles and Border Collies do better when neutering is delayed until beyond one year of age. For large and giant breeds, the recommended delay is longer. German Shepherds, Boxers, and Standard Poodles benefit from waiting until at least two years, and Bernese Mountain Dogs should ideally wait well beyond two years.
Golden Retrievers and Labrador Retrievers fall somewhere in between. Male Golden Retrievers should wait until beyond one year, while male Labs benefit from waiting until at least six months. Your vet can help you weigh the specific risks for your dog’s breed, size, and individual health profile.
Cats are more straightforward. Most veterinary organizations support neutering cats at around five months of age, before they reach sexual maturity and begin spraying.
How Safe the Procedure Is
Neutering is extremely safe. A study of nearly 114,000 dogs and cats at a high-volume clinic found that the overall mortality rate was 0.03 percent, or about 3 deaths per 10,000 surgeries. Males had an even lower risk than females (0.02 percent versus 0.05 percent), largely because the male surgery is less invasive. Dogs fared better than cats, with a mortality rate of just 0.009 percent.
The most common complications aren’t life-threatening. They include minor swelling at the incision site, mild infection, or reactions to the anesthesia like temporary nausea. Serious complications are rare when standard protocols are followed.
What Recovery Looks Like
Most pets are groggy for the first 12 to 24 hours after surgery. By the next day, many are acting close to normal, which is actually the biggest challenge of recovery: keeping them calm enough to heal properly.
Your pet needs to stay on restricted activity for 10 to 14 days. That means no running, jumping, rough play, swimming, or bathing. Strenuous movement can cause swelling around the incision, pull sutures loose, or reopen the wound. Leash walks for bathroom breaks are fine, but anything beyond that should wait.
An Elizabethan collar (the plastic cone) is the most reliable way to stop your pet from licking or chewing the incision, which is their natural instinct and the single most common cause of post-surgical complications. The cone should stay on for the full 10 to 14 days, even if your pet seems to be leaving the incision alone when you’re watching. Many pets lick at it overnight or when left alone.
Keep the incision dry and check it daily. A small amount of redness and mild swelling in the first few days is normal. What isn’t normal: discharge, a foul smell, the incision opening up, or swelling that gets worse instead of better after the first 48 hours. Most pets are fully healed and back to their normal activity level within two weeks.