The use of natural betaine to mitigate heat stress in sows

Performance declines during the summer

4 Min Read
Submitted by AB Vista

It is well-documented that sow reproductive performance declines during the summer and this can manifest itself in multiple ways. Heat stress can cause a reduction in nonproductive days and is often linked to a delay in estrus, failure to return to estrus or embryo losses after mating. Heat stress in summer can also result in a 0.05 piglet reduction for every 1° C above 20° C at insemination as well as reduce farrowing rate. This, coupled with reduced lactation feed intake in high temperatures, results in greater tissue mobilization, resulting in a negative energy balance thereby impacting subsequent reproductive performance. Hence, looking at environmental or nutritional ways to mitigate heat stress in sows is key to minimizing the drop in reproductive performance associated with summer.

One nutritional solution that has had success in this area is natural betaine. Betaine, or tri-methyl glycine, is a methyl donor and osmoregulator. As an osmoprotectant, betaine prevents water flow to the lumen, maintaining enterocyte hydration and integrity. This helps support and maintain nutrient absorption during challenges, which, in effect, is an energy-saving process. In addition, as a methyl donor it helps convert homocysteine to methionine. This not only provides a methionine-sparing effect if the homocysteine pool is sufficient but, more critically, it reduces the level of blood homocysteine that is raised during oxidative stress which is often associated with elevated environmental temperatures (Sahin et al., 2003).  It is believed that high levels of circulating homocysteine has a negative effect on conception rates and implantation and that betaine may be beneficial in maintaining lower levels of blood homocysteine.

Furthermore, follicle development and timing of ovulation are indicators of the reproductive performance of sows, and it has been shown that heat stress reduces follicle diameter. In contrast, the use of supplemental betaine has been shown to increase follicle diameter (Cabezon et al., 2017), which is important in determining weaning-to-oestrus period, with slower follicle growth being associated with a longer wean-to-oestrus period. Indeed, this is supported by research that has shown that the addition of betaine in lactation can reduce the wean-to-oestrus period (Ramis et al., 2011, Greiner et al., 2014, Cabezon et al., 2016).

Betaine has been shown to be effective in reducing blood circulatory homocysteine levels with a recent study in boars showing that 3 kg/t of betaine reduced homocysteine levels by 28% (42.3 ummol/l v 30.7 umol/l, P < 0.05; Cabezon et al., 2016). Studies have also confirmed the ability of betaine to maintain better gut integrity through improved cell hydration (Augustine and Danforth, 1999) and enhanced tight junctions (Wang et al., 2020) Furthermore, betaine has been shown to increase villi height and the ratio of villus height to crypt depth of the small intestine (Slade et al., 2004, Wang et al., 2020) in pigs.

Based on the mechanistic ways in which betaine can ameliorate the impact of heat stress, the application of betaine in lactation during summer heat stress has increased in the industry with the focus on improving the subsequent number of pigs born. A summary of five studies using natural betaine is shared below (Table 1).

Table 1. The effect of natural betaine (2 kg/t) in lactation on subsequent piglets born 

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These studies show that the use of natural betaine in summer lactation improves total pigs born on the subsequent farrowing period, with this effect being more pronounced in the older parity sows. This also translates to more pigs born alive with Ramis et al, 2011 and Campbell and Virtanen, 1996 showing significant increases in born alive with betaine supplementation in lactation. Further larger-scale trials similar to trial 1 would be beneficial in determining the consistent significant response of betaine on pigs born, but the summary data so far shows that betaine could be used as a nutritional tool to reduce the typical sow reproductive fall-off associated with summer heat stress. With the average benefit of 0.6 pigs born extra on the subsequent farrow after betaine has been fed in lactation, the current economics would suggest that the use of betaine can provide a conservative economical ROI of > 10:1.


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