The Colostrum Chronicles: Identifying Porcine Milk Oligosaccharides in Colostrum and Investigating Their Role in Litter Performance

In commercial pig production, sows have been selectively bred to become hyper-prolific. However, litter size is positively associated with pre-weaning mortality rate; often due to factors such as intrauterine growth restriction, limited teat availability, and unequal access to colostrum. Colostrum plays a critical role in neonatal survival, providing not only passive immunity but also bioactive compounds such as porcine milk oligosaccharides (PMO), which exhibit prebiotic and immunomodulatory properties. While human milk oligosaccharides have been successfully added to infant formula, the potential application of PMO in piglet milk replacers remains underexplored. This study aimed to characterize PMO in colostrum from 45 hyper-prolific Large White x Landrace sows (parity 2-8) and investigate their associations with litter performance metrics, including pre-weaning mortality and piglet bodyweight. Colostrum was sampled and pooled from multiple teats per sow at the on-set of farrowing. Using LC-MS/MS, 11 PMO structures were identified and analysed via mixed regression models. Litter size was a significant but modest predictor of lacto-N-neotetraose (LNnT) concentration (R2 = 0.198; P = 0.0143), with concentration decreasing as litter size increased. Higher concentrations of 2'fucosyllactose (2'FL) appeared to reduce pre-weaning mortality rate, although the significance of this diminished after false discovery rate adjustment. Despite this, our findings suggest that specific PMO play a role in early litter performance. Despite all sows being managed within the same herd, with similar genetics, there was considerable inter-sow variation in colostrum composition. Further research is needed to assess whether supplementing piglet diets with targeted PMO could enhance outcomes in large litters, where competition may render natural concentrations insufficient to exert measurable effects.