467 Early <i>Bacillus</i>-based probiotic exposure in swine starts with the sow, and benefits both reproductive and growing swine

Abstract Early Bacillus-based probiotic exposure in swine commences with the sow and confers advantages to both reproductive and growing swine. Previous studies by Lerner et al. (2020), Bertram et al. (2022), and Kinsley et al. (2024) have demonstrated the efficacy of pre-farrowing probiotic administration in supporting normal pig growth, particularly in the face of viral disease challenges (P &amp;lt; 0.05). These investigations underscore the crucial role of the pre-farrowing and lactating sow in delivering Bacillus-based probiotics, thereby seeding the environment, and exposing suckling offspring to beneficial Bacillus spores. While the practicality of extending pre-farrowing administration beyond gestation-lactation diet transitions may be limited, literature suggests notable benefits associated with prolonging sow exposure to Bacillus-based probiotics prior to farrowing. Studies by Alexopoulos et al. (2004) and Link et al. (2016) have reported enhanced piglet/litter weights during lactation and at weaning (P &amp;lt; 0.05), reduced incidence of sow interventions in lactation (P &amp;lt; 0.05), and a tendency to mitigate litter diarrhea severity with a 14-d pre-farrowing Bacillus-based probiotic regimen (P &amp;lt; 0.10). Moreover, extending the pre-farrowing administration to 31 d has yielded additional advantages, as evidenced by Lerner et al. (2020), including increased d 1 body weight (BW; P &amp;lt; 0.05) and a strong tendency for greater d 17 BW (P &amp;lt; 0.07). Over the past 5 yr, six studies utilizing a similar 31-d pre-farrowing administration of BioPlus 2B (B2B) have consistently demonstrated tendencies towards or statistically significant improvements in weaning weights compared with controls, with an approximate 0.22 kg weaning weight benefit across studies (P &amp;lt; 0.05). Limited information exists regarding the transition from 31-d pre-farrowing application to full reproductive herd implementation. However, preliminary findings from Kinsley et al. (2023) in an observational study of a four-site, 8,500-sow system suggest positive outcomes including reduced pre-weaning mortality (P &amp;lt; 0.01), improved farrowing rates (P &amp;lt; 0.01), and increased pigs weaned per litter (P &amp;lt; 0.001), associated with B2B application. These results corroborate previous findings by Kritas et al. (2006), Alexopoulos et al. (2004), Link et al. (2006), and Lilija et al. (2012), which have consistently demonstrated benefits such as reduced pre-weaning mortality, heavier weaning weights, and reduced BW loss during lactation with B2B supplementation. Furthermore, recent studies examining the impact of pre-farrowing probiotic delivery on nursery performance metrics have indicated favorable trends in average daily gain (4.7% greater) and feed conversion (1.5% less) with B2B sow application, although statistical significance was not achieved. These findings collectively emphasize the potential of early Bacillus-based probiotic exposure in enhancing swine health and productivity across multiple stages of production.