Lameness: The Leading Identifiable Reason for Sow Mortality
Ongoing research aims to provide clarity on why sows die. What’s challenging about sow mortality is the largest contributor to mortality is a bucket of reasons labeled “unknown.”
“There are many reasons why sows die that no one has a good understanding of,” says Corey Carpenter, account manager at Zinpro. “But the leading identifiable reason is lameness. It’s the first reason people can actually identify why sows die.”
The modern sow is expected to maintain optimum performance to keep generating at the levels they are today, explains Benny Mote, University of Nebraska-Lincoln assistant professor and swine Extension specialist.
“Any hiccup in health or structure or anything that will keep them from getting feed or maintaining peak performance, will have a negative impact on that sow’s well-being, health and productive life,” he says.
Sound feet and legs are needed to get up and down in crates, as well as to find the feeder in loose sow housing.
Why is Lameness Still an Issue?
Lameness is a multifactorial issue. It can be caused by everything from the management and environment of the sow to gilt development to nutrition to genetics, just to name a few. “Naturally, we gravitate toward the ones we know we can control or that we have the most knowledge on,” Carpenter adds.
Big expansions in sow numbers are one reason Mote believes lameness continues to be a challenge.
“On some big sow farms, we’ve had big depop-repop events due to health,” Mote says. “When you do that, you’re taking a large number of females on an influx when they come back into those farms. When you take large numbers, no matter how good your multipliers are, you never build in enough cushion. You push selection rates because of the large need for gilts at the sow farm and send gilts that would have otherwise been sold as market hogs.”
The pork industry is teetering on the edge like the supply chain during the pandemic: just in time. 2020 showed the world that rarely works.
“We’re running our multipliers at ‘just enough,’” Mote says. “We need to get away from the plug-a-hole mentality and find gilts that will give us three parities. If they don’t, they aren’t paying their bills.”
3 Areas to Watch
1. Group housing
For decades, the industry has selected gilts for confinement raised off of sows in crates. Now the industry needs sounder females than ever, especially considering the steps sows will take in larger, 200-sow pens, Mote says.
“They have to walk around and make their rounds to be able to get feed and water. We’re asking them to do something completely different than where the industry has been the past 30 to 40 years,” he says. “We have a learning curve there. When you move into these big pens, if they’re a little bit lame, they may get picked on and they may not make as many trips to the feeder to get their allocation.”
He says the industry is making these group environments better, for example pointing slats a certain way in the alleys because of how sows walk.
“It’s a different game now because we’ve also lost some husbandry skills by moving pigs indoors,” Mote says. “If we go where Proposition 12 is pushing things, where sows don’t get to be in stalls during breeding, they are going to be riding each other and fighting in a very critical stage.”
Of course, this will happen after the big nutrient demand of lactation that can potentially lead to brittle bones and weak joints. Simply put, it’s even more important to find sound replacements.
2. Nutrition
Mote and his team of graduate students have been studying how feeding gilts different rations to get gilts growing on two different planes affects feet and leg structure over time. Unfortunately, this long-term project just came to a halt due to a disease challenge, Mote says. “Some of
the things we did identify, however, are that gilts’ feet and leg structure changed over time. We saw animals get a little more cushion to their pasterns and hocks as they aged. We also saw that with gestational stage,” he says. “One of the other neat things we noticed was toe length was changing.”
Marking the toes, they tracked how the toe was growing or wearing across various time points. Early results showed a cyclical upward trend in total toe length throughout the sow’s reproductive lifetime, with exponential growth taking place from the midpoint of gestation throughout weaning and rapid wearing from weaning back to the midpoint of the following gestation.
“Some people are trimming toes and dewclaws,” he says. “Knowing you get a cyclic pattern in toe growth dependent on gestational stage could help for knowing when to trim and when to wait.”
Scientific literature also provides evidence certain types of complex minerals can reach target tissues.
“When you break down the physiology of the claw and foot, and why lameness occurs, there’s a relationship between the value minerals provide and those target tissues,” Carpenter says.
But this doesn’t mean you can just provide more of those trace minerals. Absorption is critical, he says. There’s gene expression for “I need more zinc, and I need to send it to the claw.”
3. Genetics
Many structure traits have a 0.2 or 0.3 heritability, so we can make good progress on improving structural soundness through genetics, Mote says.
“The challenge is accurately getting the phenotype on the traits in a timely manner to make selection decisions on it. That’s where the industry has struggled,” he says. “Some genetic companies are obtaining more true phenotype measurements they can use for selection. The next step is we have to do more automated phenotyping.”
Computer vision allows for the capture of some metrics now such as stride length and angles. Mote believes the opportunities ahead are exciting to capture more phenotype data.
“Walk a gilt past a camera to get her side view and pick up stride length,” he explains. “When she stops, it gets feet and leg angles. Then, compare to historic data that shows animals with XYZ angles tend to last X long. And use that to help make decisions.”
He’s quick to point out the industry can’t ever get away from good selectors, but technology can provide an extra buffer to help producers make progress.
Mote says the pork industry can’t afford to let the lameness issue worsen.
“We have to be extremely careful as an industry not to lose our social license on sow mortality,” Mote says. “We need to address it as an industry before we get a negative light on it.”
More from the Synergy on the Sow Farm Series:
Can Genetic Selection Lower Incidence of Uterine Prolapse in Pigs?
Study to Investigate Potential Mechanisms that Control Uterine Prolapse Susceptibility
What's it Worth to Reduce Your Herd’s Stillborn Rate?
Ease Your Gilts into Electronic Sow Feeding Systems
