Previous studies have shown increasing soluble fiber intake pre-farrowing reduces sow constipation and stillbirths. While raw materials high in soluble fiber are costly and hard to source, stimbiotics may offer a potential way to enhance fiber fermentability and deliver similar benefits. This experiment aimed to evaluate the effects of feeding sows a blend of common fiber sources and/or stimbiotics before farrowing and during lactation on sow constipation, colostrum quality, and fecal dry matter (DM). 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 either 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=246 g/d, 372 g/d prefarrow for CON and FIB, respectively), starting 1 day after entering farrowing stalls until weaning. A five-point scale was used to assess daily constipation scores (DCS) from entry into farrowing stalls until weaning. The scale ranged from 0 (absence of feces), 1 (dry, pellet-like feces), 2 (slightly dry feces), 3 (normal, soft feces), to 4 (wet, non-firm feces that are still formed). An incidence of pre-farrow constipation was defined as receiving two consecutive scores of 0 prior to the farrowing event. A subsample of 120 focal sows, evenly distributed between treatments and parity, was selected for sample collection. At loading, day 5 post-treatment, day 10 post-farrowing, and weaning, fecal samples were collected. Colostrum was sampled within 24 hours of farrowing and measured with a BRIX refractometer. Continuous data were analyzed using a linear mixed model, and categorical data used odds logistic regression. Diet, stimbiotic, time and their interactions were used as fixed effects, and farrowing room as a random effect. Dietary treatment did not impact colostrum BRIX refractometer percentage (P=0.199). Supplementing a stimbiotic did not alter constipation score (P=0.401), or incidences of constipation (P=0.712). By day 3 of supplementation, a greater proportion of sows fed FIB had a DCS of 2 or 3 prior to farrowing (P< 0.05). Similarly, FIB supplementation decreased incidences of pre-farrow constipation by 27% relative to CON (P=0.012). Post farrowing, FIB supplementation reduced DCS of 0 and 1, by 22% compared to CON (P=0.04). There was no difference in fecal DM% at loading, but by day 5 post-treatment, FIB supplementation had reduced it by 8% compared to control (P=0.019). In conclusion, supplementing sows with a blend of wheat-middlings and soyhulls effectively reduced pre-farrow and post-farrow constipation scores and fecal dry matter content.

Self, R., A. Waller, L. Merriam, P. Wilcock, S. Becker, R. Schmitt, B. Williams, J. Flohr and A. Petry. 2025. Increasing fiber intake with a soyhull and wheat middlings blend in the pre-farrowing and lactation periods reduces constipation severity in sows and impacts fecal dry matter. 2025 American Society of Animal Science Midwest Section meeting, Abstract 72.