Cat Neutering Side Effects

Cat neutering is the sterilization of the pet and is a method to control the feline overpopulation. In males the procedure can also be called castration, while the removal of the ovaries in females may also be called spaying or ovariohysterectomy. The neutering procedure may have short and long term side effects.

Short Term Side Effects

The neutering procedure in felines is simple and will have minimal side effects. The cat may experience pain post surgery, but the vet will prescribe suitable pain medications.

During the surgery, the pet may lose blood, but this may not happen if the procedure is performed with lasers.

Other post operatory side effects of the neutering surgery include redness and swelling of the surgery wound, infections (that may be treated with antibiotics) and scarring.

In rare cases, the surgery may not be successful and the vet will need to perform a second neutering procedure. Opt for a reputable surgeon to ensure that your pet is in safe hands.

Weight Gain

Weight gain may be a long term side effect of cat neutering. After the surgery, the cat will no longer spend time searching for a partner to mate, so the cat will be more sedentary. If the cat eats the same amount of food, he will gain weight.

You should discuss with your vet and make some changes in your cat’s diet; you should reduce his calorie intake, without affecting the amounts of essential nutrients that your pet needs.

Lack of Activity

As the cat will no longer be interested in mating, he will spend more time indoors. Male cats tend to become aggressive when they fight for a female or a territory. After being castrated, the cat will be less aggressive and will sleep more.

The lack of activity may lead to obesity.

You should get your pet used to new indoors activities to help him be active. Initiate different games; get some toys and encourage your pet to be active.

Stunted Growth

The stunted growth may be a side effect of the neutering process, but it is rare. This may happen only if the neutering is performed too early. Consult your vet to determine the optimal time to perform the neutering of your pet. The best time to neuter cats is just before they reach sexual maturity (before the first heat cycle in females).


Cystitis or urinary infections are more common in neutered cats. In rare cases, male cats may experience urinary blockages. To prevent these, the vet may recommend a wet diet and you should also increase the cat’s water intake.

These side effects are minimal when compared to the many benefits of the neutering surgery. In addition to preventing unwanted pregnancies, the cat’s behavior will be calmer, he will fight less, roam less, be less vocal and the spraying behavior may also stop. The neutering surgery will also reduce the chances of reproductive system cancers.