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* The domestic sow is generally polyoestrous, but the wild pig is a seasonal breeder with the main breeding season occuring in autumn with another peak in April.
 
* The domestic sow is generally polyoestrous, but the wild pig is a seasonal breeder with the main breeding season occuring in autumn with another peak in April.
 
* There is some influence of photoperiod on reproduction in the domestic sow.
 
* There is some influence of photoperiod on reproduction in the domestic sow.
** Anoestrus occurs more commonly in summer and less commonly in February.
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** Anoestrus occurs more commonly in summer and less commonly in February and March.
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** Ovulation rate is lower in summer.
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** Artificially reducing the day length from May-August will decrease the interval from weaning to oestrus from 23.6 days  on average to 5.7 days.
    
=== Cyclic Changes in the Ovaries ===
 
=== Cyclic Changes in the Ovaries ===
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