ISSN 2398-2977      

Female: shortened diestrus

pequis

Synonym(s): Shortened interestrus interval


Introduction

  • Cause: shortened diestrus due to the failure of the corpus luteum can result from endometritis, endotoxemia, iatrogenic therapy, or cervical/uterine manipulations.
  • Signs: early return to estrus.
  • Diagnosis: palpation and ultrasonography of the reproductive tract; supportive laboratory testing where appropriate, eg cytology, bacteriology.
  • Treatment: treat cause.
  • Prognosis: depends upon cause.
  • See also Uterus: endometritis - bacterial.

Pathogenesis

Etiology

Pathophysiology

Normal reproductive physiology

  • Diestrus has an average duration of 16 days, and extends from ovulation to luteolysis.
  • Following ovulation, plasma progesterone concentration Endocrine: hormone assay - female increases from 0 ng/ml to 8 ng/ml by day 5. Peak concentration of 5-20 ng/ml is achieved between days 5 and 8 and maintained until days 14-15.
  • Progesterone exerts a negative feedback on gonadotropin releasing hormone (GnRH) which in turns decreases the concentration of luteinizing hormone (LH).
  • Follicle stimulating hormone (FSH) is unaffected and often peaks mid-diestrus.
  • Prostaglandin F2 alpha is released from the endometrium in the absence of pregnancy and → lysis of the corpus luteum.
  • A rapid decline in plasma progesterone concentration follows which initiates estrus by 'unmasking' estrogen.
  • Normal physiology is disrupted, resulting in shortened luteal phase/diestrus, for the following reasons: endometritis → inflammation of the endometrium → prostaglandin synthesis and release → luteolysis → premature return to estrus. Any mare that exhibits shortened diestrus should be assessed for endometritis:
    • Acute inflammation is more liable to cause early return to estrus than is chronic inflammation.
    • Contagious equine metritis Uterus: contagious equine metritis is a transient, but acute, infection which → decreased interestrous intervals in most cases.
Degenerative endometritis/endometriosis/uterine fibrosis however can → decreased release of prostaglandin, thus causing prolonged (rather than shortened) diestrus. In pregnant mares, endotoxemia can induce fetal death mediated via an PGF2α-induced reduction in luteal function.
  • Cervical/uterine manipulation:
    • For example uterine biopsy, non-surgical transfer of an embryo can result in leuteolysis by provoking a release of PGF2α.
    • Administration of a non-steroidal anti-inflammatory, eg flunixin Flunixin meglumine may reduce this prostaglandin release.
  • Iatrogenic therapy:
    • Treatment with exogenous prostaglandin F2α on day 5 or later after ovulation will cause luteolysis and thus shortened diestrus.
    • Treatment with exogenous prostaglandin F2α as early as day 1 or 2 post-ovulation can disrupt normal formation of the corpus luteum, and result in shortened diestrus.

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.
  • Crowell-Davis S (2007) Sexual behavior of mares. Hormones and Behavior 52 (1), 12-17 ScienceDirect.
  • Daels P F, Stabenfeldt G H, Kindahl H & Hughes J P (1989) Prostaglandin release and luteolysis associated with physiological and pathological conditions of the reproductive cycle of the mare: a review. Equine Vet J 21 (S8), 29-34 VetMedResource.
  • Koskinen E, Kuntsi H, Lindeberg H & Katila T (1989) Predicting ovulation in the mare on the basis of the follicular growth and serum estrone sulfate and progesterone levels. Zentralbl Veterinarmed [A] 36 (4), 299-304 PubMed.
  • Lofstedt R M (1988) Control of the estrous cycle in the mare. Vet Clin North Am Equine Pract 4 (2), 177-196 PubMed.

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