Rethinking sow and piglet care in hyper-prolific litters

Genetic success creates trade-offs

The genetic push to increase litter sizes has dramatically changed pig production. Over the last few decades, the number of piglets born per sow per litter has jumped by 4 to 6 piglets in many commercial systems. But as the number of piglets increases, the average birth weight often decreases.

“Pigs are a litter species – they’ve always had a few small piglets or runts of the litter,” said Dr. Baxter. “But breeding for higher numbers born has had an effect on the average birth weight, but also the within-litter birth weight variation. We have more of these smaller, tail-end piglets.”

The reason? Simple biology. There’s just not enough space in the uterine horn, so the piglets are sharing resources. The distribution has now shifted to lower birth weight.

“Genetic selection is the main trigger,” Dr. Baxter said. “Environmental, nutritional and health factors can also affect birth weight. But pushing for larger numbers born has been the main factor.”

And while birth numbers have gone up, the benefits of genetic selection for more piglets born haven’t always followed.

“On the whole, I would say it isn’t working,” she said. “The numbers that are being born to the sow need so many more interventions by the staff. They can also need quite specialized interventions and it can be very overwhelming – not only for the animals themselves but also for the staff.”

Piglet survival begins with the sow

While the spotlight often lands on piglets, Dr. Baxter argues that true progress begins with the sow.

“These girls are involved in a marathon,” she said. “What used to be a two- to four-hour farrowing with births every 20 minutes has turned into seven to eight hours for some sows.”

Prolonged farrowing leads to increased risk of stillbirths, oxygen deprivation and meconium aspiration syndrome (MAS) – particularly for piglets born last in the queue.

Dr. Baxter emphasizes proper sow preparation as essential.

“Sows need to be as fit as they can going into farrowing,” she said. “They’ve got to prep for a marathon. You’ve got to eat right, you’ve got to drink, and the other thing I always say is – don’t do drugs.”

She’s referring to the widespread use of oxytocin to help labor along.

“There's going to be a temptation to pop oxytocin in her if she's struggling to give birth, but that needs to be managed. There’s plenty of data to show that it actually causes more problems,” she warned. “It can cause more stillbirths, and it can be incredibly painful for the sow.”

Instead, Baxter encourages high-fiber transition diets, access to nesting material and freedom of movement prior to farrowing.

“All of that helps with the process,” she said. “And really importantly, it helps with things like constipation, which is one of the big issues sows have when transitioning from their pregnancy environment to farrowing.”

Colostrum: Time to watch the clock 

Once piglets are born, you’re on the clock.

“Get them warm and then get colostrum in them soon after birth,” said Dr. Baxter. “The best quality colostrum is in that first four hours.”

Every piglet needs at least 250 grams of colostrum to acquire the antibodies necessary to fight off infection.

“We’d say 300 grams would be better for survival and thriving,” she added.

But colostrum is limited. “Selection for large litter size has not come with an equivalent increase in colostrum yield,” Dr. Baxter said. “And it’s difficult to milk a pig.”

Moreover, the window for absorption closes rapidly. “After two days, the piglet’s gut closes,” she explained. “If they haven’t had enough colostrum by then, you’re just giving them nutrition not immunity.”

If considering moving a piglet or a group of piglets, Dr. Baxter recommends that newborn piglets have consumed colostrum from their birth mom before being moved.

“It's much more efficient if they can suckle from their own mother first, so they can absorb the IgG (Immunoglobulin G),” she explained. “This is really important from an immunity perspective. Ideally, piglets should have four to six hours suckling their own mother's colostrum before moving to a nurse sows or foster sows.”

The art of observation

In large-scale operations, staff must make critical decisions across dozens of farrowing pens every day. Dr. Baxter advocates for a structured approach.

“What would really help on farm is to have those decision support trees,” she said. “Make sure piglets are at the udder, check if they’re suckling, feel their bellies—are they full?”

She recommends basic tools: colored marker pens to track which piglets have suckled, with heating mats and proper ventilation.

“You’ve got to keep the farrowing house at 20–22°C. The piglets need warmth, but the sow must not overheat,” she emphasized. “Dry piglets off, use straw or a substrate—get them warm first. Only then can they absorb colostrum effectively.”

Piglets that don’t get warm and feed quickly face hypothermia fairly quickly. Dr. Baxter encourages staff to look beyond size alone.

“It’s not just low birth weight piglets at risk,” she emphasized. “Some of the big ones are vulnerable too.”

Some larger piglets may suffer from oxygen deprivation or meconium aspiration syndrome (MAS) – a condition where fetal waste is expelled and inhaled during birth.

“They might be tinged with brown or spotted,” she said. “They’ve suffered compression of the umbilical cord, taken a breath in utero, and aspirated fecal matter. They can be quite vulnerable.”

These piglets need warmth, colostrum and close monitoring.

Split suckling and teat order

In large litters, split suckling is one of the most valuable tools. It involves rotating subsets of piglets on and off the sow to ensure everyone gets access to colostrum and milk.

“She’ll be letting down milk continuously for 12 hours after farrowing,” said Dr. Baxter. “You can divide the litter, let half suckle for an hour and the other half keep warm, then switch.”

But timing is critical, and so is organization.

“You need good people in your farrowing house—people who are diligent and observant,” she said.

Teat fidelity—the idea that each piglet picks a specific teat and stays with it—is essential to long-term stability.

“When it’s disrupted, you get squabbling, stress and unstable suckling. That’s when the sow gets up and down, which leads to more crushing,” she explained.