Piglet Management and Feeding Strategies to Protect Post-Weaning Health and Improve Performance

At birth, piglets are severely immunodeficient and rely heavily on maternal colostrum and milk for immune protection, development, and survival (Stokes et al., 2004). Since it takes newborn piglets approximately three to four weeks to acquire maternal immunoglobulins from ingested colostrum for passive immune protection (Rooke & Bland, 2002), when challenged with pathogens, neonatal pigs generate limited T and B cell responses due to the functional immaturity of their cellular and secretory immune systems (Butler et al., 2002).

Therefore, the weaning phase is quite a challenging and stressful period for piglets which results in profound changes in gut microbiota, host physiology, and mucosal immune function (Li et al., 2018). The gastrointestinal tract is an essential part of the immune system of piglets, as the intestinal immune barrier functions as the first line of defense against invading pathogens (Morris & Choudhry, 2021).

Keeping piglets healthy and nourished is possible by sustaining good immune development. However, it is no easy task because their immune systems can be affected by several factors. The more pigs a sow produces, the worse is the growth of their litter (Pere & Etienne, 2000). Similarly, Smit et al. (2013) found that the more piglets a litter has, the lower their weight at birth and the more variation there is in piglet birth weight within the litter. Also, analyzing data from 20 different studies from 1992 to 2018, Oliviero et al. (2019) observed an increase in farrowing duration when litter size increases. Finally, because colostrum production is not influenced by litter size (Oliviero et al., 2019), hyper-prolificacy has limited the micronutrient and immunoglobulin transfer from the sow to her pigs.

Regarding sows, their feed quality and content can influence the vitamin status of the piglets at birth and weaning, considering that maternal nutrition plays a significant role in neonatal development, lactation, and offspring productivity (Zhang et al., 2019). Thus, the robustness and maturity of the piglets are significantly impacted by this, which in turn significantly impacts their immune acquisition. Also, as up to 70% of immune cells are located in the intestinal mucosa and submucosa (Fumess et al., 1999), strategies must be designed to colonize the gut of the piglets early in order to instill immunity.

Considering all those factors, it is critical to understand the immune systems of piglets in order to maximize their health, welfare, and performance. Supporting their immune systems through nutrition is a great approach. An efficient approach targets piglet immune competence development through microbial colonization of the gut and systemic immune transfer from sows to piglets. Developing immune competence requires essential nutrients and sufficient intakes using a  well-managed nutrition program to produce heavier and stronger piglets at weaning. Optimizing the nutrition for all sows is important but, with larger litter-sizes, the ability to provide supplemental milk and/or creep feed can also increase nutrient intake and immune competence in the piglets. Also, with antibiotic growth promoters being reduced, the supplementation of various feed additives – including probiotics, prebiotics, vitamins, enzymes, among others – has been shown in various studies to positively influence growth performance and gut health in young pigs after weaning (Upadhaya & Kim, 2021). 

All in all, piglets are born with an underdeveloped immune system, so they rely heavily on colostrum and milk to survive, grow, and develop. During weaning, piglets are challenged and stressed, which affects their gut microbiota, host physiology, and mucosal immune response. Therefore, understanding their immune systems is crucial for optimizing their health, welfare, and performance. It is possible to support the immune system of piglets and produce them heavier and stronger at weaning through alternative nutrition solutions, including the nutrition of sows, milk replacers, and creep feed. Also, probiotics, prebiotics, vitamins, enzymes, and other feed additives can increase growth and gut health of piglets after weaning.