Stewarts says need to focus on getting more milk in mid-weights, counting functional teats and achieving thriving, not surviving.

Ann Hess, Content Director

September 23, 2022

6 Min Read
Piglets Nursing  (1).jpg
National Pork Board

In the United States, 30 to 35% of pigs that are born are never marketed due to losses across the lifespan.

“As we're producing more pigs, we are not able to keep as many alive either, so our preweaning mortality is increasing at a fairly similar rate,” said Kara Stewart, Purdue University associate professor of animal science.

During the Birth to Market Livability session at the Allen D. Leman Swine Conference in St. Paul this week, Stewart told attendees she is a firm believer that colostrum is one of the best tools to increase survival.

“One thing it provides is the calories that that piglet needs to live, so it has all of the nutritional things we think about, as well as those immunoglobulins to provide some immune function for that piglet, but there's a lot of other things that are in colostrum that we really don't know a lot about that we call bioactive factors,” Stewart says.

Those unknown bioactive factors include growth factors, hormones, enzymes and cytokines. While the importance of breast milk in humans has been very well documented, Stewart says pigs are most likely getting some of those same benefits through colostrum, such as an improved immune function, better joint and muscle development, and a healthier digestive system.

“Pigs that consume more colostrum survive better, not only to weaning, but beyond weaning and all the way to market,” Stewart says. “They have much higher increased growth rates, especially in the lighter birth weight piglets. As a productive female, they have more piglets born alive, and they have a younger age of puberty.”

Risk factors for a reduced colostrum intake include light birth weights, large litter sizes, a restless sow or sow with poor milk production and piglets that can’t regulate their body temperature or were born late in the birth order.

While 200 grams of colostrum has been established as the industry standard needed for piglets 1 kilo and above to survive, Stewart sees more opportunity in focusing on the 1.0 to 1.5 kilo piglets.

“The 1-1.3 kilo piglets that consume 200 grams or less of colostrum have a pretty high mortality rate, but if I can get those piglets to just drink more colostrum, their mortality rate becomes the same as the higher birth weight piglets, into the 4% range,” Stewart says. “We have a lot of opportunity if we can get those pigs to just drink more milk.”

Stewart references a recent study she conducted with The Maschhoffs, where birth weights less than 1 kilo had a very high pre-weaning mortality rate. However, when they examined how many pigs were actually born into that category, it was only about 10% of the total piglets born.

“If you look at the 1 to 1.5 kilo piglet birth weights the pre-weaning mortality looks a little bit better, but at the end of the day, they were actually 55% of all of the piglets born and accounted for 50% of the mortality in the whole study,” Stewart says. “In my opinion, this is our opportunity group of pigs. I think that we have these extremely small pigs that are going to be pretty hard to save, maybe for other factors that colostrum can't fix here. We have good-looking pigs that if I can get enough milk in them, they can really survive.”

Stewart says it’s also time to start talking about survival versus thriving. Where the 200 gram colostrum limit is well known to be the cutoff for what a piglet needs to survive, what level is effective for thriving?

“Looking at what it takes to become a thriving replacement female, we might need to hit more of a target closer to 300 or 350 grams of colostrum for the piglet to survive and thrive,” Stewart says.

What management practices can help move the needle and get pigs to drink more milk? Common industry strategies have been drying piglets, split suckling, strategic crossfostering, supplementation of colostrum or milk replacer and piglet nursing behavior stimulation. While its often said anecdotally these strategies can improve mortality, Stewart says she is not so sure if improvement is actually driven by an increase in colostrum intake.

“I know a lot of the large production systems have done their own work on most of these management practices, but it's not really shared with the academic community,” Stewart says. “From what I can tell, there aren't a lot of these that actually increase colostrum intake in the piglet. However, we do put people in the barns, and we give them a job with a lot of these management practices, and therefore, I think survival maybe is improved, but not from the reasons that we originally thought, which was getting those piglets to drink more milk.”

Stewart says it’s important to note each additional functional teat can provide about 324 grams of additional colostrum.

“That is enough, in my opinion, to have one more piglet survive and thrive, because we can hit that 300-gram mark,” Stewart says. “This is an opportunity I see going forward, one to start counting and measuring functional teats, which I'm not sure we all do yet. But also in the genetics world, it's a heritable trait that we can select for, increased number of teats, and if we're going to have more pigs, we should probably have more teats.”

However, if each teat is only going to yield enough for one more piglet, then more piglets should not be placed on a sow than functional teats available.

“I think as we start to adopt new technologies and develop them in the pig industry, we have lots of opportunities for cameras and sensors to help us identify the piglets that have not received enough colostrum and to make sure we can do some extra supplementation for them,” says Stewart.

She points to the dairy industry as an example, where a test was developed to see whether a calf has received enough colostrum (Beam et al. 2009). In pigs, immunocrit, a blood sample that measures the amount of passive transfer in the piglet, can be tested. In a recent study, Stewart and her team looked at piglets in the 1.3 to 1.5 kilo birth range and fed them varying amounts of colostrum for 24 hours. The immunocrit measures were similar for those piglets with low intake colostrum levels.

One area where technology can come into play is to start identifying those piglets that received very low or barely adequate amounts of colostrum, that are not able to regulate their body temperature at 24 hours, she says.

Finally, Stewart says there is an opportunity is to measure biomarkers in colostrum intake, specifically the metabolome.

“We started studying the metabolome of the pigs and looking at the lipids in their vaginas. So, we're giving them pap smears at various ages, and we found that there's a direct correlation between the lipids and the pig’s vagina and their nutritional intake in the first 24 hours of life,” Stewart says. “That pattern of lipids in their vagina is actually still present at weaning, so we firmly believe that it is a measure of their nutritional environment.”

About the Author(s)

Ann Hess

Content Director, National Hog Farmer

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