ISSN 2398-2985      

Prolonged estrus

4ferrets

Synonym(s): Persistent estrus or heat, Hyperestrogenism


Introduction

  • Cause: female ferrets are seasonally polyestrous and induced ovulators, remaining in estrus until they are mated or for as long as daylight lasts longer than 12 h.
  • Signs: alopecia, vulvar swelling, pale mucous membranes.
  • Diagnosis: history and clinical signs, hematological profile.
  • Treatment: administration of hCG, GnRH or a deslorelin implant; ovariectomy/ovariohysterectomy
  • Prognosis: good in ferrets with a PCV of >25%; fair to guarded in ferrets with a PCV of <25%.
  • Persistent estrus is a well-known endocrine condition that affects sexually mature, non-neutered female ferrets.
  • It is characterized by elevated concentrations of feminizing sex hormones such as estradiol, estriol and estrone that may result in pancytopenia.
  • Hyperestrogenism due to prolonged estrus is relatively rare in the United States and other countries where most ferrets are surgically neutered when they are 5-6 weeks of age.

Pathogenesis

Etiology

  • Female ferrets are seasonally polyestrous (breeding season lasts from March to August) and induced ovulators. As a result, they remain in estrus until they are mated, or for as long as daylight lasts longer than 12 h.
  • The prolonged estrus and associated hyperestrogenism may subsequently result in an estrogen-induced bone marrow suppression of the erythroid, myeloid and megakaryocytic cell lines, and thus pancytopenia.
  • As a result, females are at risk of developing life-threatening anemia Anemia overview Aplastic anemia and blood loss due to thrombocytopenia if estrus persists over longer periods of time.
  • On occasion, hyperestrogenism may also be encountered in neutered ferrets of both genders as a result of hyperandrogenism Hyperadrenocorticism/hyperandrogenism, or in females with remnant ovaries or ovarian tumors.
  • Bone marrow suppression associated with hyperandrogenism is generally mild.
  • Females with ovarian remnant syndrome could potentially develop prolonged estrus.
  • Not all females in estrus that have not been mated will develop prolonged estrus:
    • In those where prolonged estrus is seen, approximately 50% will develop aplastic anemia Aplastic anemia.
    • Overall, it has been reported that 30% of females in estrus will die in a reproductive season if no male is available for copulation and no treatment is done in females with prolonged estrus.

Predisposing factors

General

  • Entire female.

Diagnosis

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Van Zeeland Y R A, Pabon M, Roest J & Schoemaker N J (2014) Use of a GnRH agonist implant as alternative for surgical neutering in pet ferrets. Vet Rec 175 (3), 66 PubMed.
  • Bernard S L, Leathers C W, Brobst D F & Gorham J R (1983) Estrogen-induced bone marrow depression in ferrets. Am J Vet Res 44 (4), 657-661 PubMed.

Other sources of information

  • Schoemaker N J & van Zeeland Y R A (2017) Disorders of the Endocrine System. In: Ferret Medicine and Surgery. Ed: Johnson-Delaney C A. CRC Press, USA. pp 191-218.

Related Images

Want more related items, why not
contact us

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code