Tattoos Indicate Spay And Neuter


It won’t be long before more people have them than don’t.

Today, though, we’re talking about dog and cat tattoos.

These tattoos are not for decoration, but for conveying information.

Discreet, painless tattoos are performed while the patient is still under anesthesia.
Discreet, painless tattoos are performed while the patient is still under anesthesia.

Veterinarians use small, straight-line tattoos when pets are spayed or neutered to let future caregivers know that this particular pet no longer has internal reproductive organs.

Suppose circumstances, economic, medical or catastrophic made it necessary that your pet go to live with someone else. You may or may not be able to convey to the new owner whether your pet had been surgically altered.

Suppose, now, that the new owner observes problems with the pet and his new veterinarian suspects that those problems may be related to the reproductive tract. Do you want your pet to have to undergo a surgical exploration of the abdomen for organs that aren’t there? A little tattoo, a couple of millimeters wide and a couple of centimeters long answers that question as soon as it is asked.

“But my pet will have a scar showing that she’s had surgery, won’t she?”


Maybe not.

Another example of a spay tattoo. Notice that the surgical incision barely left a scar.
Another example of a spay tattoo. Notice that the surgical incision barely left a scar.

Some surgical incisions heal so well that no evidence is left behind that entry was ever made.

Even if there is a scar, it only tells us that there was interruption of the skin there.

Is the scar from an injury?

Is the scar from a Caesarean section?

Is the scar from bladder surgery?

There are only three ways to know: surgical exploration (painful and invasive), hormone assays (expensive) and tattoo (free and performed after surgical alteration while the patient is still under general anesthesia). Which do you want for your pet?

While it might seem that it would be obvious in the case of male dogs and cats, a condition called cryptorchidism demonstrates the necessity of a tattoo for them, too.

Cryptorchidism occurs when testicles fail to enter the scrotum and instead are retained in the abdomen. If neither the left nor the right testicle leaves the abdomen a scrotum will never be formed and a veterinarian is left to wonder whether the pet was neutered very early in life or has testicles in the abdomen.

Retained testicles are predisposed to two types of cancer and a condition called torsion of the testicle. Torsion results in a painful, potentially life-threatening condition that requires immediate emergency surgery.

A male pet presented for abdominal pain, with no testicles in the scrotum and no surgical tattoo may undergo unnecessary abdominal surgery looking for a torsed or cancerous testicle that isn’t even there.

So, when your pet’s doctor recommends a small, discreet surgical tattoo with your pet’s alteration surgery, don’t hesitate to say yes, although, like everything about your pet’s medical care, the decision is up to you. Tattoos are optional.

Dr. Randolph.

PS: A reader asked how to remove the small amount of ink left on her pet after tattooing. When we perform a tattoo, a small amount of ink always runs out onto the skin and hair. We find it’s easily removed with 3% hydrogen peroxide.


  1. We just had our dog spayed and prior to the surgery we asked to not have her tattooed but when she came out she had a dark green line tattooed and the ink had spread to over a 2 inch area on her abdomen. We’re pretty upset about it because it looks like a very messy job and we had requested to not have her tattooed. Does the ink that spread from this tattoo go away over time and just the line remain or is it all permanent? Now that it’s on there and there’s not much we can do about it, we suppose we’re ok with a simple green line but the excess ink looks absolutely terrible.

    • I’ve never seen or heard of that. I’m a strong advocate of spay/neuter tattoos. As I say in the article, I’ve seen too many cases where we either re-operate or just have to wonder. Just yesterday we had a stray kitty who had a green tattoo we could see through her hair, and that saved her from having hormone testing and surgery. Many dogs will have enough hair to cover the tattoo and make it less noticeable. I hope that’s the case for you. Thanks for reading, Dr. Randolph.

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