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| === Restoration of the Endometrium === | | === Restoration of the Endometrium === |
| | | |
| + | * During puerperium the uterus returns to its nongravid size and the endometrium is restored to provide a suitable environment for the establishment of a new pregnancy |
| + | * This uterine involution is generally completed within 3 weeks of farrowing. |
| * 1 day after farrowing, the uterine epithelium is low columnar or cuboidal. | | * 1 day after farrowing, the uterine epithelium is low columnar or cuboidal. |
| ** Extensive folding present during pregnancy | | ** Extensive folding present during pregnancy |
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| ** Also signs of cell division, responsible for regeneration of the epithelium. | | ** Also signs of cell division, responsible for regeneration of the epithelium. |
| * Complete and capable of sustaining another pregnancy after 21 days. | | * Complete and capable of sustaining another pregnancy after 21 days. |
| + | * An delayed restoration of endometrium and uterine involution can have a negative effect on sow reproduction. |
| | | |
| === Return to Ovarian Cyclicity === | | === Return to Ovarian Cyclicity === |
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| * 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 | | * 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. | + | * 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. |
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| ** 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. |
| + | * Anoestrus and ovarian cysts in early weaned pigs may be due to the lack of a preovulatory LH surge |
| * 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 | | * 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. |