Feeding a whole-cell inactivated yeast to gestating and lactating sows in a commercial production system.

A total of 606 sows (PIC 1050) and their progeny (PIC 1050 × 280) were used to determine if feeding gestating and lactating sows a proprietary strain of as a whole-cell inactivated yeast product (; CitriStim, ADM Animal Nutrition, Quincy, IL) improves sow and litter performance in a commercial production system. Once confirmed pregnant at d 35 post-breeding pregnancy check, sows were fed a basal gestation control () diet (0.55% SID lysine) or the control diet fortified with 0.15% of the WCY replacing corn in the CON diet. Dietary treatments were also fed in lactation (1.05% SID lysine) once sows were moved into farrowing crates on approximately d 112 of gestation until weaning. Sows supplemented with WCY in gestation and lactation had increased total born piglets by 0.45 pigs ( < 0.04), piglets born alive (14.27 vs. 13.85; < 0.04), and, therefore, heavier born alive litter weights ( < 0.001) compared to CON fed sows. A greater post cross-foster litter size ( < 0.001) meant that litter size at weaning was increased by 0.54 pigs when sows were fed WCY compared to CON ( < 0.001). However, litter weaning weights and 21-d adjusted litter weaning weights were similar ( > 0.158), although numerically greater, for WCY fed sows. Pigs from CON fed sows were 0.35 kg heavier at weaning compared to pigs from WCY fed sows ( < 0.001). This increase in weaning weight of pigs from CON fed sows is partially explained by their 0.93 d longer lactation ( < 0.001) and may also be due to the smaller litter size throughout lactation. The percent of litters treated for scours decreased from 38.3 to 14.2% when sows were fed WCY ( < 0.001). The distribution of birth and weaning weights was not impacted ( > 0.2461) by treatment. In conclusion, feeding gestating and lactating sows a proprietary strain of as a whole-cell inactivated yeast product increased the number of pigs born and weaned, and decreased the prevalence of scours during lactation.