Lactation in pigs is a critical period, because it has a great impact on pig health, survival and growth at weaning and repercussions at the end of the production period.

During the last decades, lactation in pigs has been shortened. Nowadays, weaning takes place when piglets are 28 days old, or even earlier. This early weaning has some advantages and disadvantages:

It increases the number of gestations per sow each year and, therefore, improves farm’s efficiency. It also prevents lactating sows from losing too much body condition, to avoid fertility and gestation problems in the following reproductive cycle.

Regarding the disadvantages, the reproductive organs have less time to recover after the farrowing, which can affect fertility in the next inseminations. Moreover, piglets are smaller at weaning and have less time to get used to solid diets.

Any factor that negatively affects piglet’s development during the first weeks of life will make it harder to get used to the new diet and impact weight and uniformity, parameters that, most of the times, conditionate the economic income of a farm.

This is why it is so important that the sows produce high quality milk and that piglets receive the right amount of it.

Milk has two main functions:

• Nutritive function: milk is the first and only food that the piglet received during the first weeks of life, so it must contain all the nutrients necessary during this period.
• Protective function: colostrum contains a high concentration of immunoglobulins or immune effects that bring immunity to the newborns. This immunity disappears progressively as the animal grows and develops its own immune system.

1. MILK NUTRITIONAL QUALITY

Milk is a complete feed that nourishes the piglet during the first stage of life. It supplies nutrients, particularly fat and protein, as well as vitamins and aminoacids, essential for the development of the piglets.

Milk quality depends on multiple factors. Feed, gut health and the liver are among the most important ones.

Feed

Milk production is a very demanding process. In fact, for the sow to produce high quality milk, the diet has to be well-balanced and adjust to the sow’s requirements and limited intake capacity.

If the diet does not supply the required amount of all nutrients, the sow will lose excessive body condition during lactation, which will negatively impact the following reproductive cycle.

Gut health

A well-balanced diet is of little help if the sow’s gut is not working properly, as nutrients will not be absorbed. This is why it is very important to maintain the digestive system in an optimal condition.

Moreover, some disorders that can affect milk production, such as the metritis-mastitis-agalaxia (MMA) syndrome, can origin from a disbalance of the digestive flora, which can lead to mammary infections.

There are many factors that can affect the digestive system. Depending on their origin, the main ones can be classified as follows: toxic (e. g. mycotoxins), infectious (bacteria such as E. coli, or protozoa, such as coccidia) and pronutrient deficiencies.

Pronutrients are active molecules of a botanical origin capable of stimulating the physiology of the organs. They can be classified into 10 groups depending on their target cell, and intestinal conditioners are the ones affecting the cells of the digestive mucosa (enterocytes).

Feeding animals with extracts containing a specific amount of pronutrients stimulates enterocyte regeneration and function, which, in turn:

• Make sure that the mucosa is in a good status for proper diet utilization.
• Increase resistance to infections: cells are new and more resistant. There is a smaller amount of undigested feed in the gut, so less substratum for the growth of pathogens.

The liver

The liver is the organ in charge of protein synthesis and fat metabolism, two of the milk’s main components. It is also an entrace “gate” for many substances, as it filtrates all components absorbed in the gut and eliminates residues. For this, the liver is constantly in contact with toxic substances.

It is essential to prevent the effects of hepatotoxic substances, such as mycotoxins, to optimize the liver functioning. This can be done by adding to the feed mycotoxin binders with a broad-spectrum of action and effective throughout all the digestive tract. One example is Silicoglycidol, a modified silicate molecule that binds mycotoxins to prevent them from being absorbed and damage the animals.

Another factor that improves liver physiology is the administration of liver conditioner pronutrients, active molecules from a plant origin. They stimulate hepatic function and regeneration. Field trials showed that the addition their addition to the diets of lactating sows positively affects weight and survival at weaning, all thanks to a better milk quality (table 1).

2. MILK IMMUNOLOGICAL QUALITY

At birth, piglets are weak and small. Their immune system is immature, which means it is uncapable to defend the organism.

Another fact that worsens this situation is that pigs have an epitheliochorial placenta, which does not allow the transfer of antibodies or immune cells from the sow to the fetus. Because of it, resistance to infections and immune development in piglets depends a 100% of the immune cells and immunoglobulins in the colostrum.

Colostrum

Colostrum is the first milk the sow produces that is segregated after farrowing. It contains antibodies to protect the newborns, as well as the nutrients they require.

Colostrum transfers maternal immune cells to the piglet and promotes the development of systemic and mucosal immunity. This passive immunity of a maternal origin, also called lactogenic, is essential because the piglet’s immune system will get mature, and it will not be completely functional until weaning, even later.

How to improve colostrum quality

There are different mechanisms to improve the immunologic status of colostrum:

• Vaccination of pregnant sows: vaccine stimulate the production of antibodies against infections in sows, which are excreted through the mammary gland and reach the newborn. This way, piglets get protection against specific infections.
• Immunobooster pronutrients: they can whether be used alone or in combination with vaccines. Their administration during the last third of gestation in sows has been proved to increase the production of specific immunoglobulins and their concentration in colostrum. This way, piglets are more protected and it is possible to replace additional vaccinations that are used to improve colostrum quality.

3. CONCLUSIONS

Lactation in pigs is a very demanding process, as milk contains a high concentration of nutrients and, in the case of colostrum, of immune effectors.

This is why weaning is a broadly used technique in lactation in pigs that has some advantages, such as a better maintenance of body score in sows and the possibility to increase the number of births per year.

Milk quality and milk intake are essential factors to make sure early weaning is successful. Milk quality depends on its immunological and nutritional profiles, the latter depending of feed formulation and on the intestinal and hepatic functions.

Pronutrients are active molecules from a botanic origin that improve milk and colostrum quality by stimulating the organs physiology. This way, intestinal conditioner pronutrients improve diet utilization and hepatic conditioners stimulate protein synthesis and nutrient metabolism in the liver, to improve milk quality. Also, immunostrimulant pronutrients in pregnant sows improve the amount of specific and unspecific immune effectors in colostrum.

These molecules are a tool that naturally improves productivity in pig farms and have a positive effect on physiology, particularly in intensive farming.