Physiology and anatomy from farrowing through rebreeding
The CL’s (corpora lutea) remain functional and secrete progesterone throughout pregnancy. ( Remember progesterone helps to maintain pregnancy).
Just prior to farrowing the uterus and its contents weigh up to 50 to 60 pounds. This includes the uterus itself, the piglets, and a lot of fluid.Typically, the sow looses about 10 to 12 % of her body weight at farrowing.
Just prior to farrowing a series of changes occur in the endocrine(hormonal)system and the CL’s cease their secretion of progesterone. ( see “How to manage difficult farrowings” on the Purdue Porkpage for more information).
After farrowing 2 major events occur
- the uterus must undergo involution( return to its normal size and clean itself of any debris or damage) to prepare itself for the next pregnancy.
- the sow’s endocrine system must gradually recover so that a new set of follicles can develop when weaning occurs.