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Created page with "=== Oestrous Cycle === * Seasonally polyoestrous * Long day breeders with a period of anoestrus beginning in late autumn. * Increasing daylight is the most important factor for ..."
=== Oestrous Cycle ===
* Seasonally polyoestrous
* Long day breeders with a period of anoestrus beginning in late autumn.
* Increasing daylight is the most important factor for inducing the resumption of reproductive activity. The first oestrus will usually occur soon after the shortest day of the year.
* If constant 14 hours of daylight is provided, the queen will continue to cycle all year round.
* Some non-pedigrees have regular oestrous cycles lasting about 3 weeks, but others show no regular pattern.
* Duration of oestrus is 7-10 days regardless of mating.
* Oestrogen concentrations increase dramatically at the time of oestrus and may double over 24 hours.
* The principle oestrogen is Oestradiol 17β.
* The rise in Oestradiol 17β corresponds with behavioural oestrus, there are no external signs of pro-oestrus.
=== Mating and Ovulation ===
* The queen is an induced ovulator, so [[Cat Copulatory_Behaviour - Anatomy & Physiology|mating]] is important in triggering ovulation.
* There are receptors in the vulva, which are stimualated by [[Cat Copulatory_Behaviour - Anatomy & Physiology|copulation]].
* This results in release of LH fromt he anterior pituitary gland.
* Only 50% of queens ovulate after a single mating, because multiple ovulations are usually required for adequate LH release.
* The ovulatory LH surge begins within minutes of coitus.
* LH peaks within 2 hours, then returns to basal levels within 8 hours.
* Further matings before the peak in LH will result in further LH release.
* After multiple matings over 4 hours or more, further matings will not result in any further LH release.
** Due to depletion of the pituitary pool of LH, or the pituitary becoming refractory to further GnRH stimulation.
* Once significant quantities of LH are reached, all ripe follicles will rupture (all or nothing response).
* Occasionally, ovulation will occur in the absence of contact with an entire tom.
** Receptors similar to those in the vulva are found in the lumbar area.
** These can be stimulated if the queen is mounted by other females or castrated cats.
=== Pseudopregnancy ===
* Sterile matings induce ovulation and result in pseudopregnancy.
* Progesterone concentrations are similar to those of pregnancy for the first 3 weeks.
* After this, progesterone levels gradually fall and reach baseline at 7 weeks.
* Oestrus will occur shortly afterwards.
* Nesting behaviour and lactation are rarely seen, but hyperaemia of the nipples is as evident as in pregnancy.
* Appetite may increase, and fat may distribute to create an increased abdominal size.
[[Category:Oestrous Cycles]]
* Seasonally polyoestrous
* Long day breeders with a period of anoestrus beginning in late autumn.
* Increasing daylight is the most important factor for inducing the resumption of reproductive activity. The first oestrus will usually occur soon after the shortest day of the year.
* If constant 14 hours of daylight is provided, the queen will continue to cycle all year round.
* Some non-pedigrees have regular oestrous cycles lasting about 3 weeks, but others show no regular pattern.
* Duration of oestrus is 7-10 days regardless of mating.
* Oestrogen concentrations increase dramatically at the time of oestrus and may double over 24 hours.
* The principle oestrogen is Oestradiol 17β.
* The rise in Oestradiol 17β corresponds with behavioural oestrus, there are no external signs of pro-oestrus.
=== Mating and Ovulation ===
* The queen is an induced ovulator, so [[Cat Copulatory_Behaviour - Anatomy & Physiology|mating]] is important in triggering ovulation.
* There are receptors in the vulva, which are stimualated by [[Cat Copulatory_Behaviour - Anatomy & Physiology|copulation]].
* This results in release of LH fromt he anterior pituitary gland.
* Only 50% of queens ovulate after a single mating, because multiple ovulations are usually required for adequate LH release.
* The ovulatory LH surge begins within minutes of coitus.
* LH peaks within 2 hours, then returns to basal levels within 8 hours.
* Further matings before the peak in LH will result in further LH release.
* After multiple matings over 4 hours or more, further matings will not result in any further LH release.
** Due to depletion of the pituitary pool of LH, or the pituitary becoming refractory to further GnRH stimulation.
* Once significant quantities of LH are reached, all ripe follicles will rupture (all or nothing response).
* Occasionally, ovulation will occur in the absence of contact with an entire tom.
** Receptors similar to those in the vulva are found in the lumbar area.
** These can be stimulated if the queen is mounted by other females or castrated cats.
=== Pseudopregnancy ===
* Sterile matings induce ovulation and result in pseudopregnancy.
* Progesterone concentrations are similar to those of pregnancy for the first 3 weeks.
* After this, progesterone levels gradually fall and reach baseline at 7 weeks.
* Oestrus will occur shortly afterwards.
* Nesting behaviour and lactation are rarely seen, but hyperaemia of the nipples is as evident as in pregnancy.
* Appetite may increase, and fat may distribute to create an increased abdominal size.
[[Category:Oestrous Cycles]]