Timing of dietary zinc additions during gestation for improved piglet survival

Feeding zinc above the sow's requirement on day 85 of gestation until farrowing can reduce preweaning mortality of piglets, while markedly decreasing mortality of low birth weight pigs, a widespread issue in the swine industry. Supplementation of zinc during late gestation is challenging in a standard sow facility due to additional labor requirements and facility design. The optimal zinc supplementation period in gestation that promotes improved pig survival and minimizes labor requirements has yet to be established. Therefore, sows were fed a standard amount of zinc or high zinc levels, either for the duration of gestation or 5 d before parturition. Preweaning mortality of piglets was unaffected by feeding high levels of zinc to sows. However, an increased percentage of pigs born alive and a decreased percentage of stillborn pigs at farrowing was observed for sows fed high zinc throughout gestation compared to sows fed the control diet or the high zinc diet fed 5 d before farrowing. Responses observed in the current study combined with those reported previously suggest that the optimal zinc supplementation period starts in late gestation. However, feeding high zinc throughout gestation may decrease piglet mortality during the parturition process.