Iowa’s hog dominance shown in federal data amid environmental concerns

Iowa continues to dominate the US hog farming market — slaughtering more than 39 million hogs last year, roughly 30% of the nationwide market, according to the US Department of Agriculture’s (USDA) annual livestock slaughter report released this week.

The report comes as researchers and health advocates say massive farms in the state are contributing to widespread water pollution and illness. Iowa’s 2025 totals were a slight dip from the more than 40 million hogs it slaughtered in 2024 but were still more than three times higher than any other state.

Illinois and Minnesota ranked second and third, respectively, in hog slaughter totals with more than 11 million each. The USDA withheld data for six states — including major hog-producing state North Carolina — “to avoid disclosing data for individual operations,” the report said. Overall, the US slaughtered more than 128 million hogs in 2025 — roughly the same amount as the previous five years.

Pork production ripples across Iowa — adding an estimated $15.4 billion annually to the state’s economy, including $5.4 billion from hog slaughtering and processing alone, according to a report last year from the Iowa Pork Producers Association.

The new federal data reinforces the scale and intensity of the industry in Iowa. Hogs are largely raised in concentrated animal feeding operations (CAFOs) and generate an estimated 110 billion gallons of manure each year.

The state has faced increased scrutiny over links between its cancer rates and the pollution coming from CAFOs — including those used for the massive hog production — and corn and soybean fields. Iowa has the second-highest rate of cancer in the nation and is only one of three states where cancer is rising, according to the National Institutes of Health.