Improving sow longevity

Tuesday, October 29, 2019

Industry experts recommend ways to maximize sow lifespans.

by Lauren Arva

As the industry moves toward group housing for sows, farmers and other industry reps continue their quest to improve sow productivity.

"In the late '80s, 35 pigs weaned per mated sow per year was like going to the moon in 1960. Mostly a dream," says Andrew Fenton, business development manager at DNA Genetics in Ontario. "As the industry moves closer to the (National Farm Animal Care Council's July 1, 2024) deadline of mandated group housing for gestating sows, it appears these new systems are also presenting challenges for sow longevity."

Producers face challenges because of conflict between animals, floors that cause sow feet and leg injuries, and a lack of knowledge about the management of new systems, Fenton says.

"Health, genetics, nutrition, and management will have to continue to improve sow longevity, working together as they always have to meet what producers need but, more and more, what consumers expect," he adds.

Recognizing the benefits

Culling a sow early leads to one of two undesirable situations, says Dr. Robert Friendship, professor in the department of population medicine at the University of Guelph.

"You have an empty spot in the farrowing room where a sow should be farrowing, or you've got a sow that should have been culled a year ago who will wean five to six pigs at best, but she's still there," he says. "The young animal that should have replaced her didn't last.

"I think the biggest cost of not having good sow longevity is a smaller litter size. There are too many gilts, or there are too many old sows that haven't been replaced."

Producers can boost the overall efficiency of their operations if they ensure good sow longevity.

For every parity a producer keeps a sow, she can produce between US$100 (C$134.90) and US$150 (C$202.36) extra profit, says Dr. Kenneth J. Stalder, a professor of swine genetics at Iowa State University.

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"Think of each sow as your own little farrowing machine. The more pigs you get out of that female, the more you can distribute her fixed cost over more pigs."

An increase in sow longevity also reduces the overall labour requirements in a farming operation, says Brady McNeil, a member of the technical and multiplication team at DNA Genetics, headquartered in Columbus, Neb.

"The most labour-intensive animals in the system are gilts," he explains. "They require the most vaccinations, take the longest to breed and can be the hardest when moving from one location to another."

Maximizing sow longevity helps producers enhance the quality of the pigs they ship. Sows pass on antibodies to their piglets and typically produce heavier litters than gilts, McNeil says.

"In turn, those offspring can perform at a higher level in finishing," he says.

Costs can fall, too. "Maximizing sow longevity reduces the farm's replacement rate," he says, so "the farm needs to produce or purchase fewer gilts."

Changes over time

Strategies for ensuring sow longevity have shifted over time and mostly for the better, industry experts say.

"I think there's probably a better awareness of how costly it is to replace sows," says Friendship. "I remember the days when people would pull gilts out of their finisher barns, so replacing a sow was relatively easy to do.

"If producers needed more sows, they would hold back some gilts from going to market and start bringing them in to the breeding herd. I think, in the farmer's view, that was not costing them a lot."

Friendship points to improvements in feed programs that extend longevity.

The ability for the sow to have free choice feed while she's lactating – and eating feed that is more suited to a highly producing sow – allows her to milk better and maintain body condition, come out of the farrowing room in good shape, be ready to breed again and fit right back in to the farrowing group, he says. "Credit goes to the nutritionists, the feed mills and the makers of feeders for farrowing rooms."

Producers also devote more attention now than in the past to sow lifetime productivity, says Stalder.

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"More and more people are looking at how much they have invested in the gilt and development," he says. More producers are looking at their herds' lifetime productivity traits than at just the number of pigs per sow per year.

Over the last 30 years, producers have gained a better understanding of managing gilts before they enter the breeding herd, says Fenton.

The industry did not discuss "gilt development units and gilt development diets … in the late 1980s and '90s," he says. "Mature gilts were sold at 90 kilograms (198 pounds) and typically bred on first heat. Sows just didn't last in the herd under this kind of management."

What can producers do?

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Gilt development can greatly influence an animal's future reproductive success, says McNeil.

The sows should be acclimatized before they enter the breeding herd, he says. This process includes a proper vaccination program which exposes the gilt to the key pathogens on the site.

So, as a first step, producers should ensure their gilt development unit facilities are properly sized to provide gilts with the necessary square footage to allow their reproductive development to occur properly, Stalder says.

Herd management is also important for sow longevity.

Producers should have robust gilts come into the herd and breed them when they're an appropriate size and age, Friendship says.

"I think producers make a common mistake. … They've got some young gilts that are just coming into heat for the first time. They're a little bit too young to breed, but producers breed these animals anyway because they fit into the group," he says.

"Starting with a good animal is probably the main thing producers can do. They should treat the sows very nicely when they farrow the first time."

Stalder agrees.

"Have some really good people work in the breeding barns for gilt development, and make sure you're getting good boar exposure on those gilts at the right time and the right weight," he says.

After farmers clear that hurdle, the primary driver of sow longevity is her reproductive success, McNeil says.

"Did she conceive a litter on the first or second mating? Did she give birth to and wean an average or better number of pigs?

"If she can do this consistently, she will be a profitable female in the herd," he says.

In some cases, however, producers are willing to give a sow a second chance to meet her reproductive criteria.

"Sometimes, if a sow aborts, it's enough that she's lost her spot," says John de Bruyn, an Ontario Pork director and Oxford County pork producer. Instead of risking another sow abortion, the producer replaces her.

"On my farm, (however), we allow them to repeat once," he adds.

Even if sows have strong reproductive success, they may leave a herd because of another key health challenge: lameness, Friendship says.

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To help avoid this problem, producers should closely watch their animals' feet and leg soundness, McNeil says.

"If the producer is creating his or her own replacement gilts, is he or she being critical enough of the purebred females? If there is a problem in the internal multiplication portion of a herd, it will be an issue in the entire population," he explains.

Farmers must identify and address lameness as soon as possible to extend a sow's lifetime, McNeil says.

"When I am walking farms, if sows favour a leg or are off feed, and I do not see any treatment records, I become concerned," he says.

"Stockmanship is critical … to maximize sow longevity."

Producers should also treat problems quickly and review culling criteria, McNeil adds.

Looking ahead

Researchers are approaching improvements to sow longevity from many sides, says McNeil.

One of the most exciting research collaborations in the swine industry is between Iowa State University and producers who are looking for common denominators that affect specific production issues such as prolapses, he says.

And genetic companies are looking at measuring traits that will increase the likelihood that a sow will have long-term success in a herd.

DNA Genetics, for example, is working with a large commercial production system to gain a better understanding of the genetics of sow longevity, McNeil adds. The system will be stocked with pedigreed F1 females and the lifetime productivity will be analyzed on over 25,000 sows in the Midwestern United States.

In Canada, Friendship is working with Chantal Farmer from Agriculture and Agri-Food Canada to examine nutrition in gilt development units.

"The one worry with reducing nutrition in gilts is the period when their mammary development occurs, so we're starting a project looking at nutrition in the growing stages of gilts and how it affects their lactation performance when they farrow," Friendship says.

Researchers are examining the practice of limit feeding to try to slow gilts' growth. Some industry reps believe this technique can reduce osteochondrosis, which is the main cause of lameness in replacement gilts, Friendship explains.

"It's something nobody has looked at because it's not easy."

Sow longevity research is important for producers like de Bruyn.

"In the old days, we just picked a pig out of the finishing barn, and she became the gilt. Then we went to raising gilts on our own, but we probably didn't raise them big enough," he says.

"Research showed us that feeding gilts differently than market hogs and letting them mature a bit more before first breeding" improves longevity.

Producers look forward to finding new information to help them drive their operations ahead as they shift to group housing. BP

Prioritizing sow longevity from the start

The factors shaping sow longevity begin when a future replacement gilt becomes a fetus in her mother's uterus, says Dr. William L. Flowers, the William Neal Reynolds distinguished professor in the department of animal science at North Carolina State University.

"Our data indicates that birth weight and pre-weaning growth have important positive relation- ships with sow longevity," he says.

Two phases shape longevity, he says to Better Pork.

"From both a physiological and management perspective, I like to think of sow longevity as having a developmental phase and a functional phase," he says.

The first phase involves the development of the significant components of the sow's reproductive system that she will use as an adult.

The phase "ends when she is bred for the first time as a gilt on a commercial farm."

The functional phase for sows begins when the animal initially mates and involves everything that the animal is exposed to while she remains in production, he explains.

"The term ‘functional' is appropriate since, after she is bred and enters production, her reproductive physiology functions to produce piglets," Flowers says.

"The analogy that I like to use is that of a car. The developmental phase is similar to building the car: the engine, transmission, brakes etc. The functional phase is similar to the skill of the driver, the road conditions and the type of gasoline that is used.

"You can have a good car but, if you have a bad driver, bad gasoline and poor road conditions, then you can't get very far."

The opposite is true as well.

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"You (need) really good management during both the functional and developmental periods to maximize sow longevity," Flowers says. BP