Canis ISSN: 2398-2942
Failure to show estrus
Synonym(s): Anestrus
Contributor(s): Carlos Pinto
Introduction
- Prolonged anestrus following puberty, complete inactivity of ovaries.
- Cause: ovariectomy, age, chronic administration of androgens or progestagens, hypothyroidism, delayed puberty Delayed puberty , idiopathic.
- Signs: primary anestrus = failure to show signs of estrus >24 months of age; secondary anestrus: failure to display signs of estrus 10-18 months after a preceding estrus.
Pathogenesis
Etiology
- Ovariohysterectomy Ovariohysterectomy.
- Systemic abnormalities → debility, eg diabetes mellitus Diabetes mellitus , hyperadrenocorticism Hyperadrenocorticism and hypothyroidism Hypothyroidism.
- Ovarian disorders: ovarian aplasia, progesterone-secreting cysts, auto-immune oophoritis.
- Congenital abnormalities of sexual differentiation.
- Drug-induced anestrus: exogenous administration of progestagens or androgens.
- Ovulatory estrus without accompanying behavioral signs of sexual receptivity (silent heat).
- Pregnancy.
- Delayed puberty Delayed puberty.
Predisposing factors
General
- See above (congenital, acquired disorders, iatrogenic).
Pathophysiology
- Ovariectomy → lack of ovarian hormones.
- Systemic disease may → hypothalamic-pituitary-gonadal axis abnormality
.
- Aging → ovarian senescence not clearly documented in the dog.
- Exogenous androgens or progestogens → chronic suppression of ovarian activity.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Bouchard G F, Gross S, Ganjam V K, Younquist R S, Concannon P W, Krause G F & Reddy C S (1993) Oestrus induction in the bitch with the synthetic oestrogen diethylstilboestrol. J Repro Fertility 47, 515-516 PubMed.
- Moses D L & Shille V M (1988) Induction of estrus in Greyhound bitches with prolonged idiopathic anestrous or with suppression of estrus after testosterone administration. JAVMA 192 (11), 1541-1544 PubMed.
- Jeffcoate I A (1983) Endocrinology of anestrous bitches. J Repro Fertility 47, 69-76 ResearchGate.
Other sources of information
- Johnston S D, Root-Kustritz M V, Olson P N S (2001)Canine and Feline Theriogenology.Philadelphia, W B Saunders Co.