Chemical Castration for Dogs: What Is It?

For dogs that can’t be operated on because of a medical condition, chemical castration may be an option.
Chemical Castration for Dogs: What Is It?
Ana Díaz Maqueda

Written and verified by the biologist Ana Díaz Maqueda.

Last update: 22 December, 2022

Surgical sterilization is the safest and most effective way to control the reproduction of dogs, as well as to prevent other illnesses. However, chemical castration is becoming a more popular way to avoid stray dogs from overpopulating.

An estimated 75% of the dog population roam freely and reproduce without any control. This can lead to serious problems, such as transmitting diseases, attacking people, and causing traffic accidents.

Chemical castration methods include hormonal drugs, immunocontraceptives, and inorganic sterilizing chemicals. All have the same objective: to prevent animals from reproducing. There are some countries that don’t allow surgical castration, therefore chemical castration is a good alternative.

Hormonal methods of chemical castration for dogs

Hormonal regulation of fertility in animals begins with a hormone synthesized in the brain called gonadotropin-releasing hormone (GnRH). As its name suggests, GnRH controls the release of gonadotropins, but also follicle-stimulating hormones (FSH) and luteinizing hormones (LH). These regulate the production of sex hormones and ultimately spermatogenesis, ovulation, and sexual behavior.

Hormonal methods of chemical castration for dogs focus on using agents that block GnRH receptors and, thus, stopping sperm production.

Treatment is usually an implant under the skin. It releases an agent that prevents the action of gonadotropin-releasing hormone (GnRH).

Immunocontraceptive method

This non-surgical castration therapy is a contraceptive vaccine. Some antibodies play an important role in reproduction. Therefore, if antigens are used to release these antibodies, we can make a dog infertile as long as there are enough antibodies in the blood.

A dog getting a jab.

Inorganic sterilizing chemical methods

Any chemical method for sterilizing males must meet three criteria. Firstly, it must be effective in all or a high percentage of treated animals. Secondly, it can’t have side effects and it needs to be safe. Finally, it needs to have a permanent and irreversible effect after one administration.

Zinc gluconate neutralized with arginine

This chemical is used chemically sterilize male dogs. It’s administered through an intravascular injection at the center of the testicle.

This medication results in permanent and irreversible fibrosis of the seminiferous tubules, rete testis, and epididymis. Therefore, the dog is sterilized. However, hormones remain intact. Visually, after a while, the testicles become smaller and change shape or texture.

Calcium chloride

One of the most commonly used chemical compounds is calcium chloride. Like the previous one, it’s injected directly into the testicle. This causes fibrosis, necrosis, and degeneration of the seminiferous tubules, so that no sperm can be produced.

It’s a very inexpensive, pain-free method, so it could be an alternative to more expensive drugs that may not be available in many countries.

Hypertonic sodium chloride

Hypertonic sodium chloride can be an economical and easy-to-administer alternative. It causes degenerative changes in testicular seminiferous tubules through an intravascular injection.

Some studies suggest that this method is better for young dogs. However, it won’t work in adult dogs.

Advantages and disadvantages of chemical castration for dogs

A cute puppy.

In some respects, chemical castration for dogs can be a great alternative to surgery. Despite this, there is also a negative side. It’s always best to talk to your vet, who can offer you the best options for your dog.

Advantages of non-surgical sterilization in the dog

  • It’s a cheaper and simpler procedure
  • It’s a good option for owners that worry about surgery
  • Animal protection organizations that help animals could sterilize many more
  • Since surgery isn’t involved, it reduces pain, stress, the possibility of hemorrhages, hernias, infections, as well as other surgical consequences
  • In developing countries, where there are no facilities for sterilization, this is a good alternative

Disadvantages of chemical castration for dogs

  • Side effects such as scrotum pain, swelling, redness, and irritation may occur
  • Other symptoms such as lethargy or diarrhea may be present
  • Sex hormones are still produced, so the male’s sexual behavior wouldn’t disappear. Certain diseases caused by these hormones can also appear, such as prostate enlargement or testicular cancer.

Chemical castration for dogs can contribute to your pet’s well-being. Check with your vet to learn more about the benefits and what kind of care you should provide to your pet once it has gone through the procedure.

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The contents of My Animals are written for informational purposes. They can't replace the diagnosis, advice, or treatment from a professional. In the case of any doubt, it's best to consult a trusted specialist.