Plus-Hex CLINICAL
ABSTRACT Female ferrets , referred to as ‘ jills ’, are seasonally polyoestrous and induced ovulators . If they are not bred , surgically neutered or chemically brought out of season , persistent oestrogen production can result in bone marrow suppression , pancytopenia and even death .
With news of the discontinuation of the drug Delvosteron , commonly known as the ‘ jill jab ’ ( licensed for ferrets and used to induce ovulation ), owners and veterinary professionals should be aware that there are alternative treatments available .
This article will discuss the alternatives available to prevent prolonged seasons in female ferrets with the aim of helping decision-making on the appropriate treatment for individual ferret patients .
Keywords ferret , oestrus , reproduction , contraception , deslorelin , hyperoestrogenism , hyperadrenocorticism , ovariohysterectomy
Female ferret reproduction
Jills are considered seasonally polyoestrous , having several oestrous cycles during a breeding season and exhibiting constant oestrus ( season / heat ) if they are not bred . Jills reach puberty at around 8 – 12 months old , with sexual maturity usually occurring during the first spring after birth [ 2 ] . The breeding season in the UK runs from March to August , although ferrets housed indoors and under artificial lighting may come into season earlier . During this time , gonadotropin-releasing hormone ( GnRH ) stimulates the production of the gonadotropic hormones luteinising hormone ( LH ) and follicle-stimulating hormone ( FSH ). These hormones stimulate the ovaries to produce oestradiol [ 1 ] .
Female ferrets are induced ovulators : release of the egg takes place only when mating occurs . The most obvious sign of a female ferret in season is a swollen vulva ( Figure 1 ). Female ferrets will remain in the oestrus phase of the cycle until they are mated or artificially stimulated to ovulate .
Introduction
The discontinuation of Delvosteron has caused concern among ferret owners , as it is used to chemically stop the signs of oestrus in female ferrets . If the oestrous cycle is not stopped by either mating , neutering or hormonal injection , female ferrets may have a prolonged oestrus that can lead to life-threatening anaemia . Commonly referred to as the ‘ jill jab ’, the subcutaneous injection of 50 mg Delvosteron ( proligestone ) per ferret will stop the signs of oestrus around 10 days post injection . It will prevent oestrus for one full season in 92 % of patients , with the remainder needing a second injection [ 1 ] .
Ferret owners have been seeking information and guidance from veterinary professionals on alternatives to Delvosteron . Although surgically neutering female ferret patients before they come into season might seem to be the easiest solution , that is not necessarily the case . Female ferret reproduction is complicated and there is conflicting advice about the various available treatment options . This article will review the available treatment options in the UK so that veterinary nurses ( VNs ) can advise owners and help them make informed choices about how to prevent prolonged seasons in their jills .
Learning outcomes
• Understand the basics of female ferret reproduction .
• Evaluate alternatives to Delvosteron for female ferrets and know how and when to use them .
• Confidently discuss alternative treatments with ferret owners on an individual , case-by-case basis .
Figure 1 . Swollen vulva of a female ferret 2 weeks into season . The ferret had been presented for an injection of Delvosteron .
Persistent oestrus over 4 weeks typically results in hyperoestrogenism ( persistently high levels of oestrogen in the blood ), leading to bone marrow suppression and a life-threatening aplastic anaemia [ 3 ] . Clinical signs may include bilateral symmetrical dorsal alopecia , vulval swelling , vulval discharge , pallor , melaena and petechiae [ 4 ] . There are several options available to avoid illness associated with prolonged seasons in the female ferret .
Volume 39 ( 4 ) • August 2024
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