Sow diets rich in fermentable fiber may improve farrowing kinetics; however, U.S. fiber sources are largely unfermentable. Stimbiotics may address this gap by driving microbial degradation of insoluble fiber. The experimental objective was to evaluate total dietary fiber and stimbiotic supplementation during the periparturient period and through lactation on litter performance and piglet viability. A total of 860 sows (25% parity 1, 38% parity 2-3, and 37% parity 4+) were assigned to a randomized complete block design with a 2×2 factorial treatment arrangement. Factors included a top dress of corn (CON) or an equal blend of wheat-middlings and soyhulls (FIB) supplemented with (+) or without (-) a stimbiotic (0.15% Signis; AB Vista, Marlborough, UK). Sows received 227g of top dress twice daily (0.454 kg/d) alongside their lactation diet (TDF = 246g, 372g for CON and FIB fed sows, respectively), starting 1 day after entering farrowing stalls until weaning. Litter performance was collected throughout the experimental period. Litter viability was assessed at 24- and 72-hours post-farrowing on a 4-point scale, with 0 indicating no reduced viability and 4 indicating four or more. After farrowing, only sows with piglets cross fostered within treatment group remained enrolled in the study (N=640). Count data were analyzed using a negative binomial generalized linear mixed model fit for overdispersion, and categorical data used odds logistic regression. Diet, stimbiotic, parity, and their interactions were used as fixed effects with total born as a covariate, and farrowing room as a random effect. Number of mummies did not differ among treatments (P>0.1). There was a trend toward a diet by stimbiotic interaction for stillborns (P=0.056); sows fed FIB or CON with stimbiotic supplementation tended to have reduced stillborn rates (1.04, 0.83, 0.75, and 0.84 stillborns per litter for CON-, CON+, FIB-, and FIB+, respectively). Likewise, CON- increased lower viability piglets at 24-h and 72-h post-farrow (Diet x Stimbiotic, P< 0.05). An interaction among diet, stimbiotic, and parity was observed for born alive (P=0.039). FIB supplementation increased born alive, but CON+ improved born alive specifically in parity 1 sows. There was a tendency for a diet by stimbiotic by parity interaction for pigs weaned per litter (P=0.066). Parity 1 sows fed CON+ tended to wean nearly a pig more per litter than CON- (11.1, 12.0, 11.4, and 11.6 pigs per litter for CON-, CON+, FIB-, and FIB+, in parity 1, 11.0, 11.6, 11.4, and 10.9 for parity 2 and 3, and 11.3, 11.3, 11.0, and 11.3 for parity 4+, respectively). Similarly, preweaning mortality tended to be reduced by 18% in parity 1 sows fed CON+ (Diet x Stimbiotic x Parity, P=0.054). Collectively, fiber and stimbiotic supplementation in the periparturient period improved farrowing performance, but effects through lactation were parity dependent.

Self, R., A. Waller, L. Merriam, P. Wilcock, S. Becker, R. Schmitt, B. Williams, B. Williams, and A. Petry. 2025. Fiber or stimbiotic supplementation during the periparturient period and through lactation enhances sow farrowing and litter performance but with parity-dependent benefits for weaning outcomes. 2025 American Society of Animal Science Midwest Section meeting, Abstract 74.