Review article

Management of the sexual cycle and treatment of sexual cycle disorders in female ferrets (Mustela putorius furo)

Monika Jukić ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska
Ivona Žura Žaja ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska
Juraj Grizelj ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska
Marko Samardžija ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska
Dražen Đuričić ; Veterinarska stanica Đurđevac, Hrvatska
Silvijo Vince orcid.org/0000-0002-1883-3225 ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska

Abstract

Ferret females are seasonally polyoestrous animals. Melatonin secretion regulates the start of the breeding season in March and its com- pletion in August, when the daylight begins to shorten. The first sign of oestrus in female is the swollen red vulva with thick white vaginal discharge. Since most ovarian follicles begin to mature 10 to 14 days after the beginning of oes- trus, this is the best mating time. Ovulation is copulation-induced and occurs 30 to 40 hours later. In addition to copulation-induced ovula- tion, hormonal injections of hCG and GnRH can be used to induce ovulation. They are ad- ministrated 10 or more days after the onset of oestrus. If the oestrogen concentration remains high for less than 4 weeks, oestrus can be ter- minated with the administration of hormonal injections. In the early stages, oestrus can be stopped by performing an ovariohysterectomy when a high oestrogen concentration has not yet caused a toxic effect on bone marrow cells. If none of the above mentioned methods are applied, ovarian follicle and egg cell atresia will occur, and the oestrogen concentration will remain high (hyperoestrogenism). Oes- trogen has a toxic effect on bone marrow cells, leading to aplastic anaemia, thrombocytopenia and lymphopenia. Blood transfusion and an-
tibiotics are indicated to stabilize the animal in cases when haematocrit is less than 25% and thrombocytopenia develops. After initial stabilization, oestrus can be terminated with ovariohysterectomy. Ferrets have a tendency to develop endocrinopathies, most notably adrenal disease which includes adenoma, ad- enocarcinoma and adrenocortical hyperplasia. A positive correlation exists between the time of spaying and the occurrence of adrenal dis- ease. Persistently high concentrations of plas- ma gonadotropins (LH and FSH) after spaying before puberty have the most important role in deactivating LH receptors in the adrenal cortex and in cell multiplication. This causes a spike in androstendione, oestradiol, 17-hy- droxyprogesterone and/or dihydroepiandros- teron sulphate concentrations. The condition manifests similar to hyperoestrogenism. In order to prevent adrenal disease, slow release GnRH-agonists implants are used. With un- spayed animals, they can be used as a medical castration tool, while in spayed animals, they can prevent or slow the growth of an existing tumour. If a tumour occurs, adrenalectomy can be performed.

Keywords

ferret females; estrogen; anemia; ovariohysterectomy; adrenal diseases

Hrčak ID:

222265

URI

https://hrcak.srce.hr/222265

Publication date:

11.6.2017.

Article data in other languages: croatian

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