Sow Nutrition, Uterine Contractions, and Placental Blood Flow during the Peri-Partum Period and Short-Term Effects on Offspring: A Review

SIMPLE SUMMARY: A long birthing process is not only stressful for both the sow and her piglets, it also decreases the chances of survival of piglets during birth or in the first days of life. Oxygen supply from the mother to the fetus via placenta and umbilical cord is crucial. This oxygen supply may be impaired by successive uterine contractions, partly or completely blocking placental and/or umbilical blood flow. Providing the mother with the right amount of energy and other nutrients needed for the birthing process could reduce its duration and, as a consequence, increase peri-partum piglet survival. In addition, nutrients that enhance blood flow (and therefore oxygen flow) to piglets during birth may also impact piglet survival. ABSTRACT: The birth process is a crucial event for piglet survival. Along with increasing litter sizes, not only has the duration of parturition increased, but placental blood flow per piglet has reduced and placental area per piglet has become smaller, making these piglets more susceptible for hypoxia. Diminishing the risk of piglet hypoxia by either reducing the total duration of parturition or increasing fetal oxygenation may reduce the incidence of stillbirth and early post-partum mortality. This review discusses options to do so by nutritionally supporting the sow in the final pre-partum period, after discussing the role of uterine contractions and placental blood flow. Providing sufficient energy seems to be a logical first step, but also other nutrients needed for uterine contractions, such as calcium, or enhancing uterine blood flow by using nitrate seem promising. These nutrient requirements may depend on litter size.