Feeding the gestating sow

Theories debunked
calendar icon 25 May 2022
clock icon 4 minute read

Over the last several decades there have been several suggestions on how to feed the gestating sow, and recently several of those practices have been debunked and have actually shown to have more detrimental effects than they do beneficial effects.

I think part of the reason we have been making these discoveries is that we now have a greater understanding of the sows’ physiological processes.

For starters, one main theory that has been backed up by several studies is that the sow prioritizes the requirements of the fetus over her own nutritional requirements during late gestation.

Over the last 20 years, there have been several studies that have fed more feed during various stages of gestation, however, there was little to no differences in these studies. One study done by Buitrago et al. (1974) showed that there was no statistical difference in average piglet birth weight when feeding gestating sows 1.5 vs 2.4 kg per day during late gestation. However, bump feeding, the practice of increasing the amount of feed given to sows in late gestation, is still practiced by some swine producers.

There have been several studies as well that have shown that bump feeding has little and often no effect on the birth weight of the piglets. This again reinforces the theory stated earlier, because the sow is already giving the fetus the nutrients that it requires by metabolizing nutrients from her own body, so any extra nutrients that are fed are only going to affect the weight of the sow, not the litter.

Not only will bump feeding cost you a lot more with higher feed costs, but it can actually have a detrimental effect on the sow as well. Since she is fatter, she will tire faster during labor thus increasing the number of stillborns. It has been shown that fat sows have higher pre-weaning mortality.

A study by Thomas et al. (2018) showed that though increasing the lysine amount during late gestation did not increase birth weight, it did reduce the number of stillborn piglets. This again reinforces the fact that fat sows tire faster during labor, but a more muscular sow will have greater endurance, thus potentially increasing the number of pigs born alive. Studies have consistently shown that the more you feed the sow during gestation, the less feed she will eat during lactation resulting in her losing more weight during lactation which is not good.

We did a study back in 2016 that showed that increasing lysine during late gestation had no effect on the birth weight of the piglets, however, increasing energy intake while keeping amino acids fixed from about an equivalent of 4 lb (or 1.8 kg; 4.5 Mcal NE/day) to 6 lb (or 2.7 kg; 6.75 Mcal NE/day) increased birth weight by about 30 grams. We theorize that this slight increase in birth weight will rarely translate into a larger weaning weight as it is most likely due to increased glycogen reserves which will be quickly burnt up shortly after birth. Now let's think of a scenario that which this weight gain did follow through to market, and increased survival rate... when we ran economics we also saw that it was economically not beneficial due to the increased feed costs offsetting the economic profits from the increased performance.

Now... I do not know what you love in life... but I love The Sow Caliper.

The caliper developed by Dr. Mark Knauer is not perfect, but it does a wonderful job of estimating the body condition of the sow. There are always too many opinions and no one knows who is right. Using the caliper forces the production systems to have "one opinion" - backed by science by the way, so not really an opinion ;P

Consistency is king.

We can use that information to save money by feeding fat sows less feed to decrease body condition which will not affect the litter during late gestation.

One last thing to keep in mind, younger females have a higher amino acid requirement than older sows. Whenever possible, feeding separate diets by parity category (gilts, P1, and P2 versus P3+) can help save money by more accurately meeting the requirements of the animals and not overfeeding the sows.

That is all I had. Any thoughts?

Have a great weekend,


Márcio Gonçalves

Founder of Swine it
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