We have seen several ferrets in my clinic (www.richmondvets.co.uk) in recent months. One of the common questions from owners regards neutering and spaying pet ferrets. Ferrets are unusual creatures in that females, or Jills, are ‘induced-ovulators’. This means that they require mating to take place in order to ovulate, otherwise they can remain in season or oestrus for long periods of time. When this occurs high levels of oestrogen for months on end can lead to serious consequences including a fatal anaemia due to bone marrow suppression.
Traditionally, the solution to avoiding persistent oestrus was either to mate your Jill to a male ferret or Hob, to use a vasectomised (infertile) Hob to mate with the Jill thus avoiding an unwanted litter, spaying the Jill to remove the ovaries and therefore source of hormones, and finally the most popular method of using a ‘Jill-jab’ steroid injection to suppress oestrus each Spring before she came into season.
The problem however of spaying female ferrets is that removing the source of oestrogen creates a hormonal imbalance relating to the pituitary gland in the brain. Because there is a lack of oestrogen being produced, the pituitary gland starts to release excessive Gonadotrophin-Releasing Hormone (GnRH) in an effort to stimulate the now absent ovaries. Unfortunately, in many ferrets this overproduction of GnRH over time leads to changes within the adrenal glands and adrenal disease develops.
Male ferrets once sexually mature develop a pungent smell, greasy coat and often start spraying urine as a territorial behaviour, which makes living with them in the home quite difficult in some circumstances. Traditionally, castration was advised as a solution to these problems but again removing the testes disrupts the normal hormonal balance in the body and can lead to adrenal disease later in life. Vasectomised ferrets used for mating with females and reducing persistent oestrus problems are infertile yet retain their testicles so continue to produce testosterone and exhibit male behaviours.
Adrenal disease is reasonably common in older ferrets and can have serious side effects on other organ systems as well as being life-limiting in itself. Recent studies have shown a significant risk of adrenal disease in neutered ferrets, therefore the recommendation in recent years is to avoid surgical castration or spaying of male and female ferrets. Luckily, there is a hormonal implant developed for use in dogs which has now been licensed for use in ferrets also, therefore allowing all the benefits of surgical neutering in male and female ferrets including rendering them infertile without the added risk of future adrenal disease.
The implant itself contains a drug called Deslorelin and is slightly larger than a standard pet microchip. In most cases in order to ensure comfortable and safe insertion the ferret is given a small amount of anaesthetic gas so it is unconscious during insertion of the implant. Generally the process needs to be repeated every 18-24 months as the implant has slow release activity and eventually it’s efficacy runs out and it is absorbed by the body. There is also a stronger dose implant available which can last up to 4 years for an adult ferret.
Modern veterinary advice regarding control of reproduction in ferrets highly recommends using this implant technique rather than surgical neutering in order to reduce the incidence of adrenal disease later in life. The implant can be placed once your pet ferret has reached puberty and become sexually mature.
All the best,