Chemical Castration for Male Dogs - When Can It Be Useful?

We most often associate castration with preventing unwanted breeding, but in practice the question of castration often comes up for an entirely different reason - the dog’s behavior.

Running away from home, a strong interest in female dogs, sexual excitability, marking, conflicts with other dogs or aggressive behavior can make an owner wonder: “Maybe we should have him castrated?”

But one thing is important to understand here - castration is not a universal solution to every behavior problem.

Will my dog be calmer after castration?

Not always.

Castration mainly affects behaviors in which sex hormones play a significant role. Fear, anxiety, learned behavior, insufficient socialization or other causes of behavior will not automatically disappear after castration.

That is exactly why, when behavior is the main reason for castration, chemical - or reversible - castration can be a useful intermediate step before irreversible surgical castration.

What is chemical castration?

For male dogs, a subcutaneous implant containing the active substance deslorelin can be used.

It initially stimulates and then suppresses the hypothalamic-pituitary-gonadal hormonal axis. As a result, testosterone levels drop, the testicles shrink and reproductive function is suppressed for a certain period of time.

Unlike surgical castration, this method is reversible.

The implant is placed under the skin much like an injection, and the procedure usually requires no surgery or general anesthesia.

How quickly does it start working?

The effect is not immediate.

In the first period after the implant is placed, there may even be a temporary rise in testosterone - the so-called flare-up effect. During this time, some dogs may briefly show more sexual behavior or stronger reactions towards other male dogs.

After that, hormonal activity gradually decreases.

So if the implant is used to assess how testosterone affects a dog’s behavior, conclusions should not be drawn after just a few days. Behavior should be assessed over a longer period, once hormonal suppression has been established.

How long does the implant last?

That depends on the implant used and on the individual animal.

The 4.7 mg deslorelin implant for male dogs is intended to suppress reproductive function for at least approximately 6 months, while a higher-dose implant lasts longer.

In practice, however, the duration of the effect can vary, and in some animals hormonal suppression lasts considerably longer than the intended minimum period.

Why use it before surgical castration?

Imagine this situation: a dog regularly runs away from home, becomes very excited when he senses a female dog nearby, or the owner is worried by certain aggressive reactions.

The owner hopes castration will solve the problem but isn’t sure.

In a situation like this, chemical castration can help assess to what extent the particular behavior is linked to the influence of sex hormones.

If the problem behavior decreases significantly once hormonal activity has been suppressed, this gives the veterinarian and the owner additional information when considering the next steps.

If, on the other hand, the behavior barely changes, there is less reason to expect that surgical castration alone will solve that particular behavior problem.

Aggression doesn’t always mean “too much testosterone”

This is a particularly important point.

Aggression can have many different causes - fear, anxiety, resource guarding, pain, past experiences, learned behavior and other factors. That is why an aggressive dog should not be castrated automatically in the hope that he will become calm after the operation.

If the behavior is not hormonally driven, its real cause needs to be found and, if necessary, an animal behavior specialist should be involved.

Chemical castration is not suitable for every dog

Chemical castration is also a medical procedure, so the decision to use it is made together with a veterinarian, taking into account the dog’s age, health, reproductive status and the reason castration is being considered.

It is also important to discuss possible side effects and what we want to achieve in the specific case.

If the main reason for castration is to prevent unwanted breeding, that is one question. If the goal is to change the dog’s behavior, the situation is far more nuanced.

Before making an irreversible decision, it is worth understanding whether the problem is related to sex hormones at all.

In some cases, chemical castration can be one way of assessing that.

If you are considering castrating your dog and are not sure which method would suit your situation best, book a consultation. We will assess your dog, the aim of castration and the possible benefits and risks in his particular case.