Swine performance starts with sow milk

1. Drivers of sow milk production

A sow uses 36.6% of her body mass per year to develop her piglets and 200% to produce the milk that feeds them. It is thus important to consider not only diet formulation, but also inherent feeding behavior to manage feeding in a way that ensures optimum health and performance of both the sow and her piglets. Dietary decisions for sows should relate to her nutritional requirements at different phases – gestation, parturition, lactation etc. Feed intake should also be considered, keeping in mind that functional nutrients and additives can also play an important role.

Genetic selection is essential to the future of sow milk production and quality. Over the past few decades, genetic improvement has resulted in an increase in litter size. Larger litters naturally result in a higher milk output, which in turn impacts a sow’s nutrient requirements. For example, the number of functional teats affects nutrient requirements. Estimates from Professor Bruno Silva (Universidade Federal de Minas Gerais – Brazil) indicate that energy and lysine requirements increase in conjunction with a higher number of both teats and piglets developing in the uterus. The number of piglets and their interaction with the mother, through suckling, are also important factors affecting milk production. An increase in litter size directly correlates to an increase in mammary gland tissue, resulting in higher milk production and, thereby, higher energy requirements.

Larger litters means an increased demand for milk, for which an adequate energy and nutrient supply are essential. Unlike for gestation, feed consumption during lactation should be maximized for optimum sow productivity. Lactation performance is of course directly related to feed and nutrient intake. Water supply and quality influence milk production not only because they are correlated with body fluids, like plasma, but also because water is the main component of milk. Feed intake should not just be a focus during an ongoing lactation period, but rather should be considered as an important factor for future herd productivity. Farmers should thus make sure the sow enters her next cycle in optimum condition. With gilts, not only is optimum nutrition required for supporting milk production, but also for her continued growth and development as an immature female. Any undue nutritional stress on sows during lactation, particularly in gilts, will affect her health and longevity. Managing this stress and supporting sows through gestations can help to protect producers’ margins.

One of the key effects of heat stress is a reduction in feed intake, with sows particularly affected by nutritional deficiencies. If a palatability enhancer is used, both the average daily feed intake of the sow and the growth rate of her piglets can be improved. Optimizing ADFI allows sows to drive nutrients and energy to the mammary gland, maximizing milk production for their litters. As a result, piglets show improved growth, with bigger and heavier litters weaned.

2. Drivers of milk quality in sows

When discussing milk quality, there is less room for manipulation. A research group from the South China Agricultural University has been studying milk composition and observed that only minor changes occurred in colostrum and milk in the past 30 years. Milk macronutrient compounds do not increase with enhanced reproductive performance, which is why effective nutritional solutions can help to improve both milk quality and quantity, protecting producers’ margins during this key stage of pig production.

Heat stress is responsible for large economic losses in animal production around the world. Firstly, when high temperatures occur, water consumption increases, and feed intake decreases (thus reducing nutrient uptake). Secondly, in an attempt to dissipate heat, farm animals increase heart and respiration rates. Metabolism is severely impacted, often resulting in oxidative stress.

Selenium is very important for immunity because of its role in the production of antioxidants. Effective supplementation in sow diets improves Se levels in milk, which in turn improves the selenium status of her piglets. This can also help to counter the negative effects of heat stress in sows and piglets. Ensuring adequate and efficient supply of total sulfur amino acids (TSAA), in particular methionine, is also essential for optimal milk quality. Methionine is an essential amino acid for protein synthesis and downstream metabolites actively involved in antioxidant defenses.

3. Solutions for improving milk yield and quality

3.1 Boost milk production by stimulating feed intake

Krave is a palatability enhancer that can be used as a strategic nutritional tool to improve both sow and piglet performance by optimizing the nutritional value of sow diets. It is particularly useful at times when heat stress negatively effects feed intake, which causes a drop in margins. Krave has the following main effects:

• Promotes higher daily feed intake
• Increases milk production
• Improves litter performance

A trial done in Brazil showed that adding Krave to sow diets can increase average daily feed intake, with clear responses in milk production that were reflected in better performance at weaning.  These effects were dose dependent – greater responses were seen when a higher level was fed. It is clear from these results that both dietary nutrients and voluntary feed intake play a role in sow milk production, and that there are tools to manage them.

Table 1: Impact of feed flavor on the performance of litters during a 24d period of lactation (Silva et al., 2018; Anim Feed Sci Technol)

The impact of Krave on piglets can be further improved by linking the flavor of the sow feed and piglet feed. This concept is called sensory imprinting.

3.2 The level and source of sulfur amino acids affect milk composition

A leading research group tested a diet containing the recommended level of total sulfur amino acids (TSAA) (NRC 2012), 0.52% of digestible TSAA and two diets supplemented at a level of 0.67% of digestible TSAA, either by DL-Methionine or by Rhodimet® AT88 (hydroxy-methionine or OH-Met). Rhodimet® AT88 has been shown to be more efficient than other methionine sources during heat stress. It has been demonstrated that supplementing OH-Met has a positive impact on performance, oxidative stress, and lipogenesis.

Figure1: Milk composition at d 0 and d 14 of lactation (Xu et al., 2017; ASAS-CSAS)
 

The researchers found that throughout the 21-day lactation period, fat was not affected by diet, but protein and lactose were influenced by both the level and source of sulfur amino acids. It was observed that piglets respond to these changes in milk composition with better performance when digestible total sulfur amino acids are supplied at the level of 0.67%.

3.3 Enhancing the immune status of piglets with a Selenium supplementation

Selenium (Se) plays a key role in antioxidant defense and in the modulation of the immune system. However, the form of selenium is important. Organic Se, in the form of SeMet is the only species able to build a reserve in the body. This supports the animal’s antioxidant system, especially in stressful conditions when Se requirements increase, and feed intake is often reduced. Selisseo® is an organic form of Se that has 100% of the Se in the form of OH-SeMet, providing a highly bioavailable source of Se and maximizing Se reserves in tissues. During stressful conditions, OH-SeMet supplementation can increase antioxidant status, cell-mediated immunity, and Se storage in tissues, and this to a greater extent than other forms of Se.

Trials on sows fed different sources of Se throughout gestation and lactation showed that such a support to the antioxidant system results in more piglets born alive (+1.62 vs Sodium Selenite; Mou et al 2020).

Supplying a more bioavailable source of Se also led to a higher Se in the colostrum and therefore a higher transfer to the piglets, which was detected in their serum after 48h (Figure 2; Cardoso et al., 2023).

Figure 2: Selenium (Se) in colostrum and piglet serum after 48h

Boosting the Se status of piglets helps the young animals to thrive during the first weeks of life, resulting in more weaned piglets (+ 1.2 vs Sodium Selenite; +1.1 vs SeYeast; Cardoso et al., 2023).

The support Selisseo® provides to the immune system of piglets was further demonstrated in a trial whereby piglets from sows fed different sources of Se were challenged with E.Coli LPS. Piglets from mothers supplemented with Selisseo® showed higher interleukin 10 after LPS challenge compared to sows fed SS (Figure 3; Mou et al., 2020).

Figure 3: Selenium effect on piglet IL-10 concentration after LPS challenge

Conclusions

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