Maternal Dietary Nitrate Supplementation Lowers Incidence of Stillbirth in Hyper Prolific Sows under Commercial Circumstances

SIMPLE SUMMARY: Over recent decades, the number of piglets and, therefore, the number of stillborn piglets per litter have been increasing. Blood and oxygen supply are crucial for piglets to survive the birth process. Blood flow might be increased through vasodilation by dietary nitrate supplementation, which is known in sports nutrition to increase endurance. The current study evaluated the effects of nitrate supplementation to sows on the incidence of stillbirth at a commercial farm. In total, 120 sows received either a control diet or a diet containing 0.1% of calcium nitrate from approximately 5 days until 4 days after farrowing. The number of piglets born alive, stillborn, or that died from birth to weaning were recorded. Piglets were weighed at birth, after cross-fostering, 24 h after cross-fostering, at 3 days of age, and at weaning. Placentas were collected after expulsion and were visually scored on redness. No effect of nitrate supplementation to the sow was found on placental redness, piglet weights, and growth or incidence of death after being born. Dietary nitrate supplementation decreased the stillbirth percentage from 9.9 to 7.4%, making it a potential approach to decrease stillbirth. ABSTRACT: The objective of the current experiment was to investigate whether or not maternal dietary nitrate supplementation, a nitric oxide (NO) precursor, could reduce piglet losses under commercial circumstances. In the current experiment, 120 hyper prolific gilts and sows (Landrace x Yorkshire: Danbred) on a commercial farm in Denmark received either a control lactation diet or a lactation diet containing 0.1% of calcium nitrate (containing 63.1% of nitrate) from approximately 5 days pre-farrowing until day 4 of lactation. The number of piglets born total, alive, and stillborn, as well as birth weights, weights after cross-fostering (approximately 1 day of age), 24 h after cross-fostering, day 3 of age, and at weaning was recorded. Placentas of sows were collected after expulsion and scored on redness. No effect of nitrate supplementation was found on piglet weight, piglet growth, placental redness score, and pre-weaning mortality during lactation. Maternal dietary nitrate supplementation decreased stillbirth percentage with 2.5% (9.9 vs. 7.4%; p = 0.05). It can be concluded that maternal dietary nitrate supplementation shows the potential to decrease the incidence of stillbirth in hyper prolific sows.