Estrous cycle: different stages in domestic animals

Following the onset of puberty in domestic animals there is the development of a physiologic rhythm of the reproductive system called the “Estrous cycle”.

  • The estrous cycle of the domestic animals is divided into Four phases or periods which blend one into the other.
  • These phases are;
  • ProestrusAlso known as building a period and begins with luteal regression and end with onset of estrus.- Duration is 2-5 Days.

    – There is follicular growth and regression of CL of previous cycle (in polycyclic species).

    – Uterus enlarge very slightly.

  • EstrusEndometrium is congested and oedematous- Vaginal mucosa become hyperemic.

    – The bitch show external evidence of proestrus with vulval odema and sanguineous vulval discharge.

    – The period of acceptance of male.

    – The uterine , cervical  and vaginal glands secrete increased amount of mucus.

    – The vaginal Epithelium and Endometrium become hyperaemic Metestrus congested.

    – The cervix is relaxed.

    – Ovulation occur during this phase of cycling all domestic species exept in cow where it occurs about 12 Hours after the end of estrus.

    – Ovulation is the spontaneous process in all domestic species except in cat , rabbit and camel in which it is induced by the act of coitus.

    – During pro-estrus and estrus there is follicular growth in absence of CL  and  main hormone is estrogen .

  • Metestrus- Metestrus is the period from ovulation & formation of CL.- It is ill defined phase.

    – The granulosa cell of the ovulated follicle rise to luteal cells which is responsible for formation of CL called as luteinization.

    – There is a reduction in cervical, vagina and uterine secretion.

    – Post oestrus or metestrus bleeding occurs.

    – Cervix is relaxed.

  • Diestrus- Longest phase of oestrus cycle.- Fully functional Corpus Luteum.

    – High level of progesterone.

    – Female do not exhibit sexual receptivity.

    – The uterine gland undergo hyperplasia and hypertrophy

    – Vaginal mucosa become pale.

    – Cervix is constricted.

    – Thickening of endometrium.

    – Vaginal, uterine and cervical secretion is decreases.

For more details please download the attachment- PPT and PDF.


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