-The concentrations of selected metabolites, minerals and hormones relative to parturition were studied in 12 primiparous sows. Blood sampling was performed on days -5, 0 and +5 relative to the farrowing day. On the day of parturition (d 0), samples were taken every hour from 07.00 to 24.00 hours. All sows had an indwelling catheter in the jugular vein, and the evolution of glucose, insulin, urea, non-esterified fatty acids (UEFA), calcium (Ca), phosphorus (P), magnesium (Mg) and cortisol were studied. The concentrations of NEFA, cortisol and P were significantly higher at d 0 than at d -5 or d +5, whereas the Mg level was lower. During the expulsion of foetuses, NEFA and cortisol levels increased (+18 and +30 %, respectively), and they decreased immediately after the birth of the last piglet, to reach the initial levels observed before farrowing (around 700 (iEq ' L ' and 110 ng-niL-1 , respectively). Glucose and insulin levels remained unchanged during the expulsion of the piglets (105 ng!dL-1 and 5 glU.mL-1 , respectively), but they both increased immediately after the birth of the last animal. During the expulsion of the foetuses, the Ca concentration remained unchanged (93 mg-L-1 ), whereas the P level increased (+9 %) and the Mg concentration decreased (-7.4

-Eighteen primiparous Large White sows were selected on d 104 of gestation. Animals had either high (AP)