Effect of maternal activity during gestation on maternal behavior, fetal growth, umbilical blood flow, and farrowing characteristics in pigs

Yorkshire gilts either remained in their individual stall from d 40 to term (CON; n = 7) or were subjected to exercise for 30 min 3 times per week from mid to late gestation (EX; n = 7) to determine the impact of increased maternal activity during gestation on maternal behavior, fetal growth, umbilical blood flow, and parturition. In parity 1, maternal body composition (10th rib back fat and LM area), maternal behavior, and farrowing characteristics were recorded. In parities 1 and 2, fetal growth, fetal heart rate, pulsatility index and resistance index, and umbilical blood flow were monitored beginning at d 39 of gestation continuing to d 81 of gestation. Exercise continued until d 104. Gilts allowed to exercise sat less (P < 0.01), stood more (P < 0.01), tended (P = 0.06) to lie down less, and had fewer postural changes (P < 0.01) compared with CON gilts. Umbilical blood flow increased (P < 0.01) in EX compared with CON gilts. Moreover, gilts had greater (P < 0.01) umbilical blood flow in their first parity compared with their second. Indices of vascular resistance were not affected (P >= 0.15) by maternal treatment; however, EX gilts reached peak pulsatility index earlier than CON gilts (56.2 vs. 64.3 +/- 3.6 d). Fetal weights, piglet birth weights, placental weight, interval between piglet births, and blood lactate of newborn piglets were unaffected (P >= 0.15) by maternal treatment. Although maternal exercise during gestation in the pig increased umbilical blood flow and appeared to reduce maternal restlessness, impacts on offspring development in postnatal life are not known.