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Lactogenic immunity

Colostrum is key for the piglet’s immunity and rich in energy, hormones and vitamins, all essential for the early life of the piglet. Because there is no maternal immunity transfer through the placenta, due to the type of placenta pigs have (diffuse epitheliochorial), this needs to be acquired by the piglets through ingestion of colostrum. It is clear that the amount and quality of the colostrum is of great value. We see that colostrum yield varies from 1 to 6 kg, averaging at around 3.5 kg. Colostrum production is limited but varies with parity and age. Very important to note is that the production can be influenced by management practices. Let us first take a closer look at the colostrum itself before focusing on how you can influence it.

Immune components of the colostrum

The antibodies present in the colostrum originate from immune responses from the sow against pathogens she was previously exposed to.

Immune cells found in the mammary gland originate from precursor immunocompetent cells presented in BALT (Bronchial Associated Lymphoid Tissue) and GALT (Gut Associated Lymphoid Tissue).

The maternal immunity includes (Salmon H (2000)):

· Systemic humoral immunity; transmitted through colostrum conveying mainly by IgG

· Local humoral immunity; especially secretory IgA (IgA’s) transmitted mainly by milk (lactogenic immunity) until weaning, these IgA’s exhibit a specificity for the antigens present in the maternal digestive tract, the so-called "entero-mammary link"

· Cellular immunity; transmitted via maternal immunocompetent cells present in mammary secretions

Colostrum composition changes during the first 24 hours, the concentration of IgG reduces rapidly in the first 24 hours after parturition (Bland I.M. (2003), Peltoniemi (2019)) and the piglets intestinal capacity to absorb immunoglobulins also reduces rapidly.

Only 12 hours after birth it can only absorb 25% of the antibodies. This is known as “gut closure”. Unless sufficient colostrum is consumed, the piglet remains highly vulnerable to diseases. The transfer of IgG from the colostrum to the piglets plasma is quick and IgG are present in the piglets plasma from 4 hours after suckling, Bland I.M. (2003).

The piglets first “shield” is crucial. Survivability is associated with colostrum ingestion. This poses a challenge when we consider large litter sizes achieved with modern genetics and the fact that the colostrum quantity is limited.

Piglets require around 180 g colostrum / kg live bodyweight to improve survivability (Quesnel H. (2019)).

Piglets plasma IgG concentration at 24 hours after birth is related to colostrum intake and low plasma IgG concentration are associated with higher chances of dying before weaning, Deviller N. (2011).

The variation in colostrum intake within a litter is positively associated with litter size and bodyweight heterogeneity at birth, Declerck I. (2017).

The IgG content of colostrum can be estimated at the farm level using a Brix refractometer and some drops of colostrum. Colostrum samples evaluated with a Brix refractometer are positively correlated with the IgG level measured with ELISA (Hasan et al., 2016). This allows farmers to implement prompt interventions that help with colostrum intake (split suckling, fostering practices, and so on).

Influencing the colostrum production / intake / “quality”

As mentioned, colostrum can be influenced by some management practices.

Factors that affect colostrum production:

· Water availability

· Sow parity

· Sow health status (MMA etc)

· Stress

· Farrowing

· Temperature

· Photoperiod

 

Factors that affect colostrum intake:

· Birth weight

· Hyperprolificity

· Sow feeding

· Importance of well-being

· Premature piglets

· Aid in the farrowing process (including farrowing at night)

· Piglet hypoxia

· Sanitary factors and care of piglets

In addition to improving colostrum production and intake, we see lots of practices to improve the immune response of the sow and quality of the colostrum to better protect piglets.

We are all familiar with sow vaccines enhancing the immunity of the sow (increase IgG, IgA’s, cell mediated immunity) against pathogens that commonly challenge their progeny. E. coli and C. perfringes are some examples of the pathogens that producers immunise sows against, so that this immunity can then be passed to the piglets by colostrum. The protection passed to the piglets through the colostrum protects them against diseases and it is a balance between immunity and challenge.

Another potential intervention to improve the “quality” of the colostrum are β-glucans, preferably those derived from algae. In response to binding algae β-glucan, immune cells will become more active (activation but no overstimulation of the immune system, which would result in inflammation) in engulfing, killing and digesting invading pathogens and will initiate a signaling cascade stimulating the attraction, formation and activation of other immune cells and antibodies (immunoglobulins). The use of algae beta-glucan during the gestation period is expected to contribute to an increase in IgG, IgA and cell mediated immunity available to the piglet during the first stage of the piglets life, increasing its resilience and survivability, resulting in heavier weights at weaning and an overall improved performance post weaning.

Conclusion

When we want to improve the colostrum production, quality and intake, we need to take a concerted approach. This will ensure that sows are in top form at farrowing and through gestation with an appropriate feeding and management practices. Improving the immune status of the piglets early in life through better protection can lead to life-long health and performance benefits.

We share with you the convincing research on supplementing the sow with algae beta-glucan and the benefits for the sow’s immune status, her colostrum quality and the piglets. Click on the button below to download the research.