How to Sterilize a Dog? Techniques and Benefits

Today it's very common for dogs, whether male or female, to be sterilized. But many myths still circulate about controlling this species' reproductive cycle.

What's more, some owners aren't clear on the difference between spaying/neutering (desexing) and sterilization in the strict sense, what age is recommended, or how the procedure is done. Let's look at all the details of this type of procedure and its benefits.

Sterilization vs. desexing (spay/neuter)

Generally, we tend to use the terms "desexing" and "sterilization" interchangeably, as if they were synonyms. But the truth is there are differences between the two concepts. Sterilizing, in the strict sense, only prevents the dog from being able to reproduce, through a vasectomy or tubal ligation, which are the most common sterilization techniques.

Desexing (spaying/neutering) also prevents the dog from reproducing, but does so by removing the testicles in males, and the ovaries and, generally, the uterus in females.

In veterinary medicine, desexing is preferred, since it offers additional benefits by removing the hormones tied to the reproductive cycle. This prevents the animal from experiencing heat symptoms or developing diseases such as mammary tumors, testicular tumors, or pyometra (uterine infection).

Where can a dog be sterilized?

At veterinary clinics, it's common for the term "sterilization" to actually be used to mean desexing. Now that we've explained the differences between the two procedures, it's important to clarify with the vet, before operating on our male or female dog, exactly which procedure they plan to perform.

Keep in mind that if what we want is sterilization in the strict sense, not desexing, we won't be able to schedule this at every veterinary clinic. This is because some professionals only perform desexing, considering it the best option for the animal. That's why it's important to get clear information before going into surgery.

What benefits does sterilization offer?

The only benefit is preventing unwanted litters. Since the hormone-producing reproductive organs aren't removed, dogs can still develop all the diseases linked to these hormones, such as mammary tumors, testicular tumors, prostatic hyperplasia, or pyometra (uterine infection).

It also doesn't reduce behaviors like marking or aggressive reactions that can be linked to territoriality. Dogs will, of course, still go into heat, along with all its associated behaviors and symptoms.

What does sterilizing a dog involve?

Focusing on the sterilization procedure itself, we can distinguish chemical vasectomy or orchiectomy from an actual surgical vasectomy. For female dogs, we're talking about fallopian tube ligation or hormonal treatments.

Chemical vasectomy

This is done by injecting an irritant substance at a specific point in the reproductive tract — the tails of the epididymis. The epididymis are tubes connecting to the vas deferens, which are responsible for carrying sperm to the urethra.

Injecting the irritant causes inflammation, followed by scarring that blocks sperm from passing through. This technique has limitations and side effects, such as fistula formation or damage to nearby tissue. For all these reasons, it isn't a recommended procedure.

Chemical orchiectomy

The procedure described above can also be done on the testicles — this is chemical orchiectomy. Here, what's affected is sperm production. Otherwise, the same considerations as chemical vasectomy apply.

Vasectomy

This involves cutting the vas deferens. This cut can be made through different surgical approaches, such as abdominal or scrotal. It's a simpler operation than desexing, but shares similarities such as the need for general anesthesia or post-op care.

Another difference is that the dog will keep his sexual behavior intact. He'll still react to females in heat and be able to mount them, though no fertilization will occur. On the other hand, since hormone production continues, the dog can still develop diseases linked to sex hormones, such as testicular tumors or prostatic hyperplasia.

Lastly, it's worth noting that with this technique, a cut vas deferens can spontaneously reconnect. In that case, we wouldn't know it, but the dog would become fertile again.

Fallopian tube ligation

In females, the fallopian tubes are responsible for carrying eggs to the uterus. If they're cut, the eggs can't meet the sperm, meaning fertilization — and therefore pregnancy — is prevented. The female dog can't reproduce but will still go into heat.

None of the benefits associated with desexing occur here. For all these reasons, it's an uncommon procedure in veterinary practice, given its limited benefits compared to an ovariohysterectomy (uterus removal). It also keeps every health issue linked to sex hormones in place.

Alternative with hormonal treatments

Regularly administering hormones such as progesterone, roughly every six months, prevents the female dog from going into heat. Remember, heat is the only time a female dog is fertile. Outside those days, she can't reproduce. So, by suppressing heat, there's neither fertilization nor pregnancy.

These hormones can be given as pills or injections. The problem with this option is that it comes with numerous, serious side effects, including diabetes, mammary tumors, or obesity. Because of this, although they can be used occasionally, they're not a contraceptive method suitable for long-term use.

Precautions before surgery

Both males and females will go to the clinic on an empty stomach, since they'll be given general anesthesia. It's also recommended to run a pre-op check-up, at minimum including bloodwork and an electrocardiogram, before surgery. This helps reduce anesthesia risks and assess the dog's overall condition.

New sterilization techniques

Laparoscopy can be used for sterilizing dogs. Compared to desexing, it reduces risks, post-op care needs, and discomfort. It tends to be a more expensive procedure and requires specialized equipment and experienced staff.

Laparoscopy is done through a couple of small incisions, since it's a technique that allows visualizing the inside of the body without needing a larger opening. This way, the vas deferens can be operated on.

Post-op care

It's common for the vet to give the dog antibiotics and pain relievers to minimize discomfort and the chance of bacterial infections. We may need to keep giving these at home for a few days. Beyond that, at first we'll avoid rough play that could affect healing.

We'll keep an eye on how the wounds heal and clean them during the first few days. If we need to leave the dog alone and they lick or nibble at the area too much, we'll need to put an Elizabethan collar on them.

After a laparoscopic sterilization, the testicles may show swelling for a few days due to edema. NSAIDs are given for this. Also, over time, the testicles shrink back down from their original size.

What's the recommended age to sterilize a dog?

There are many opinions on the best time to desex or sterilize a dog. Since desexing provides hormonal benefits, it's recommended either before or after the first heat in females — that is, between 6-8 months or between 12-18 months of age.

In males, it can be delayed a bit longer, until the dog is fully developed — around one to a year and a half old.

However, since sterilization (in the strict sense) doesn't offer hormonal benefits, it can be performed at any age, though it's always best to avoid doing it once the dog is already very old or elderly.

Bibliography Carlson and Giffin. 2002. Manual práctico de veterinaria canina. Madrid. Editorial el Drac. Delgado, Jacinto. 2012. Esterilización canina mediante laparoscopia. Portal Veterinaria. Fernández, Alfredo. 2016. Guía básica para la esterilización canina y felina. Colvet.