Changes

* Vaginal epithelium and [[Uterus - Anatomy & Physiology#Endometrium|uterine endometrium]] becomes hyperaemic and congested.

* Vaginal epithelium and [[Uterus - Anatomy & Physiology#Endometrium|uterine endometrium]] becomes hyperaemic and congested.

* [[Cervix - Anatomy & Physiology|Cervix]] is relaxed

* [[Cervix - Anatomy & Physiology|Cervix]] is relaxed

* [[The_Ovary_-_Ovulation_- Anatomy & Physiology|Ovulation]] occurs during this phase in all domestic species except the cow.

* [[Ovulation - Anatomy & Physiology|Ovulation]] occurs during this phase in all domestic species except the cow.

** The cow [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulates]] ~12 hours after the end of oestrus.

** The cow [[Ovulation - Anatomy & Physiology|ovulates]] ~12 hours after the end of oestrus.

* [[The_Ovary_-_Ovulation_- Anatomy & Physiology|Ovulation]] is spontaneous in all domestic species except the cat, rabbit and camelids.  In these species it is induced by the act of [[Copulatory Behaviour - Anatomy & Physiology|copulation]].

* [[Ovulation - Anatomy & Physiology|Ovulation]] is spontaneous in all domestic species except the cat, rabbit and camelids.  In these species it is induced by the act of [[Copulatory Behaviour - Anatomy & Physiology|copulation]].

* During pro-oestrous and oestrus there is [[Ovary - Anatomy & Physiology#Folliculogenesis|follicular growth]] with no functional [[Corpus Luteum - Anatomy & Physiology|corpora lutea]] present on the [[Ovary - Anatomy & Physiology|ovary]] (aka follicular phase).

* During pro-oestrous and oestrus there is [[Ovary - Anatomy & Physiology#Folliculogenesis|follicular growth]] with no functional [[Corpus Luteum - Anatomy & Physiology|corpora lutea]] present on the [[Ovary - Anatomy & Physiology|ovary]] (aka follicular phase).

* The main ovarian hormone production is Oestrogen.

* The main ovarian hormone production is Oestrogen.

* The phase after oestrus

* The phase after oestrus

* During early metoestrus, both oestrogen and progesterone levels are relatively low.

* During early metoestrus, both oestrogen and progesterone levels are relatively low.

* Granulosa cells of the [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulated]] [[Follicles - Anatomy & Physiology|follicles]] give rise to lutein cells, which are responsible for the [[Corpus Luteum Formation - Anatomy & Physiology|formation of the corpus luteum]] (luteinisation).

* Granulosa cells of the [[Ovulation - Anatomy & Physiology|ovulated]] [[Follicles - Anatomy & Physiology|follicles]] give rise to lutein cells, which are responsible for the [[Corpus Luteum Formation - Anatomy & Physiology|formation of the corpus luteum]] (luteinisation).

* Progesterone secretion is detectable soon after [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulation]], with significant quantities produced in 2-5 days.  This marks a transition from oestrogen to progesterone dominance.

* Progesterone secretion is detectable soon after [[Ovulation - Anatomy & Physiology|ovulation]], with significant quantities produced in 2-5 days.  This marks a transition from oestrogen to progesterone dominance.

* Reduction in secretion from [[Uterus - Anatomy & Physiology#Histology|uterine]], [[Cervix - Anatomy & Physiology#Histology|cervical]] and [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|vaginal glands]].

* Reduction in secretion from [[Uterus - Anatomy & Physiology#Histology|uterine]], [[Cervix - Anatomy & Physiology#Histology|cervical]] and [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|vaginal glands]].