Pigs saved per litter numbers continue to grow as U.S. producers become more efficient.
According to the USDA, the average number of pigs saved per breeding herd animal in 2022 was 21.8, up from 18.2 pigs in 2007.
“Producers have upped the pig crop while cutting the breeding herd as a percent of the total hog and pigs inventory,” says Lee Schulz, Extension livestock marketing economist with Iowa State University.
He says the majority of the rising number of pigs per breeding herd animal has come from larger litters. Litter rates grew 1.3% annually from 2007 to 2022. Schulz says litters per breeding animal per year have plateaued since 2007 and show no signs of rising. This measure has actually trended lower recently, he says.
Schulz says pigs per sow per year is one of the most common measures of overall sow farm efficiency. Pigs per sow per year is litters per sow per year multiplied by pigs weaned per litter.
According to the USDA, the March-May 2023 pig crop, at 32.9 million head, was up 1% from 2022. Total sows farrowing during this period reached 2.896 million head, down 2.4% from 2022.
The report also indicated the average number of pigs saved per litter was 11.36 for the March-May period, compared to 11 last year.
“This is the largest litter rate ever, for any quarter, and a 3.3% annual rise is the largest since 2019,” Schultz says.
People are also reading…
While the pigs saved per litter numbers increased, that doesn’t necessarily indicate a trend, says Scott Brown, Extension livestock marketing economist with the University of Missouri.
Brown says there are likely several factors involved in the number. That includes issues with PRRS.
“I’m continuing to hear that PRRS is a problem, and that should make it tough for numbers to grow a lot,” he says. “But it is also hard to reduce the breeding herd once you’ve built the facilities. You tend to want to keep those full. Because of that, you are more likely to see sideways movement in numbers rather than growth.”
Brown says the pigs per litter numbers have been growing every month since the start of 2023. He says several Southern states, including Texas and Oklahoma, have shown considerable gains per litter. Increases have also been seen in Iowa and Missouri.
“I really don’t see it as a new trend,” Brown says. “Productivity comes from better efficiency. I really don’t think we will see more sows being added for a while.”
Other factors that could impact the numbers include complications with California’s new Proposition 12 law. Schultz says while some producers are adjusting to the housing demands, “it is too early to determine how much the change in litters per breeding animal per year in the USDA report is due to changes in sow housing and/or due to something else.
“Still, litters per mated female per year may be at or near its upper bound given recent performance and ongoing adjustments in the industry.”

Schulz says litters per mated female per year is affected by several things, including farrowing, matings and weaning age.
“Tracking those measures can identify areas for improvement,” he says. “Doing so may position managers to make improvements that can get litters per mated female per year back on an upward track.”