Deslorelin implants finally reached Switzerland in 2009. They are licensed here as a worthwhile alternative to the surgical neutering of dogs.

But why neuter a male dog? There are three main reasons:

-To prevent mating with a female nearby,

-To calm an excessive sex drive and urine marking. Note that a dog that runs off is not necessarily in the grip of excessive sex hormones!

-For medical reasons (an enlarged prostate, a testicular tumour, and so on).

Surgical neutering is still the most widely used method; it is permanent and irreversible. Its advantage is that once the stitches come out after ten days, there is nothing more to think about!

In some cases, a reversible method has its appeal:

-For a temporary testosterone-related condition, or in a very old dog, or one whose poor health makes anaesthesia risky.

-To postpone the mating of a stud dog that lives among breeding females.

-Where a behavioural problem is uncertain (running off, for instance).

The implant is placed by the vet: it is an injection of a small rod, 1.2 cm long, between the dog’s shoulder blades. The active ingredient is released steadily over 6 months (possibly longer in small breeds) and indirectly shuts down the production of testosterone and other hormones. If need be, the implant can be renewed every 6 months.

After the implant is placed, allow a delay of 6 weeks before the dog becomes infertile, as sperm remains stored for a while.

A rise in testosterone-driven effects is often seen after the implant is placed; this rise is temporary, lasting about ten days, but it can be very strong. That is why the implant is not advised in aggressive male dogs, as the aggression may increase markedly in the days that follow.

Other uses for this implant exist in other countries or on an experimental basis, with the timings and risks then varying. For example, to control reproductive function in the female dog — though the risks of this use are not yet fully established — or in adrenal gland disease (hyperadrenocorticism) in ferrets, whether male or female.

Broadly speaking, the deslorelin implant is now part of the vet’s toolkit when it comes to decisions about animals’ reproductive function, even if definitive surgery remains the option most widely used.