Impact of Maternal Parity and Direct-Fed Microbial Supplementation on Reproductive Performance, Digestibility, and Milk Quality from Early Gestation to Lactation in Sows

The experiment was conducted to determine the interaction effects of parity and DFM supplementation from early gestation (G 21) to lactation (L 21) on reproductive performance, apparent total tract digestibility (ATTD), colostrum IgA and IgG, and mature milk composition. Three hundred pregnant sows were blocked by parity (2, 3, 4, 5, and 6-9) and randomly assigned to two experimental diets in a randomized complete block design, with a control (CON, <i>n</i> = 150) group and direct-fed microbial (DFM, n = 150) group. The DFM contained 5 × 10⁷ cfu/g of <i>Bacillus subtilis</i> and 2 × 10⁶ cfu/g of <i>Lactobacillus</i> spp. Reproductive traits recorded included total born (TB), born alive (BA), litter weight (LW), piglets born dead (PBD) weaning weight (WW), number of weaning pig (NWP), and PWM. Two separate 14 d ATTD trials were conducted on G86 to G100 and L7 to L21. Colostrum samples were collected at 0, 3, 6, 12, and 24 h post-partum and mature milks were collected at L7 and L14 for Ig and composition analysis, respectively. Total Ig concentrations were measured by an ELISA. The interaction between diet and parity was found on LW, colostrum IgG, milk lactose, and protein (<i>p <</i> 0.05). Regardless of parity, sows fed DFM had greater reproductive performance with higher BA, LS, LW, and lower in PWM (<i>p <</i> 0.05). DFM also improved the ATTD of organic matter (OM), crude protein (CP), and ether extracts (EE) (<i>p <</i> 0.05) at G100 and gross energy (GE), CP, and EE (<i>p <</i> 0.05) at L21. Entire IgG and 3 h post-partum IgA in colostrum were higher in DFM than in the CON diet (<i>p <</i> 0.05). Parity effects were seen on NWP, LW, CP, and EE, colostrum Ig at 12 and 24 post-partum, milk protein, and lactose at L7 (<i>p <</i> 0.05). Moreover, the parity showed linear effect on TB, BA, LW, litter size (LS), WW, total PWM, the ATTD of OM and EE, colostrum IgG at 12 h and IgA at 12 and 24 h post-partum, milk fat at L7 and L21, and milk lactose at L14 (<i>p <</i> 0.05). Stepwise prediction for average colostrum IgG (mg/mL) by using nutrient digestibility = -112.97 + 0.706GE(%) + 0.518CP(%) + 0.267EE(%) (<i>n</i> = 267, R² = 0.38, RSD = 6.7, <i>p <</i> 0.001). In summary, supplementing dietary DFM during early gestation through weaning had positive effects on production, the lifetime of sows, and better nutrient utilization, resulting in better milk quality and better piglet growth.