13
edits
Changes
→Return to Ovarian Cyclicity
* Mostly no return to oestrus and no ovulation until piglets are removed.
* Mostly no return to oestrus and no ovulation until piglets are removed.
* Time to first ovulation can be shortened by temporary removal of the whole litter for varying periods during the day (partial weaning), or permanent removal of part of the litter.
* Time to first ovulation can be shortened by temporary removal of the whole litter for varying periods during the day (partial weaning), or permanent removal of part of the litter.
* Weaning pigs immediately after farrowing or within three weeks of delivery results in higher incidence of anestrus and a longer weaning-to-estrus interval, ovulation failure, or a reduced litter size
* Female pigs that fail to ovulate either show follicular regression or develop cystic ovarian diseases.
* Rapid regression of corpora lutea of pregnancy, with cellular degeneration occuring by 3 days postpartum.
* Rapid regression of corpora lutea of pregnancy, with cellular degeneration occuring by 3 days postpartum.
* By day 7 postpartum, corpora lutea are mainly connective tissue.
* By day 7 postpartum, corpora lutea are mainly connective tissue.
** No ovulation, follicles become atretic
** No ovulation, follicles become atretic
* Preovulatory surge of LH within 7 days of weaning.
* Preovulatory surge of LH within 7 days of weaning.
* Most of the sows resume cyclicity within a normal weaning-to-oestrus interval of less than 7 days if they are weaned after 3 weeks of farrowing
* Prolactin concentrations are high during lactation but decline rapidly to basal levels within hours after weaning.
* Prolactin concentrations are high during lactation but decline rapidly to basal levels within hours after weaning.
* Follicular growth and ovulation are supressed during lactation due to supressed LH secretion.
* Follicular growth and ovulation are supressed during lactation due to supressed LH secretion.