Study Shows Pig Farmers Improving Their Environmental Footprint Through Efficiencies

Three pigs grazing in a grassy valley with a mountain range in the background.

Photo by Sergio

DES MOINES, IOWA – Oct. 15, 2019 – A new environmental study has found that pig farms are generating less manure nutrient content associated with odor. Data gathered from more than 106,000 samples at 182 North Carolina farms shows significant reductions in ammonia levels and manure nutrient content. The improvements are attributed to gains in feed efficiency, which means it takes less feed to raise a pig.

“For an industry that is continually striving to become more sustainable, this study shows that pig farmers are making significant progress toward reducing the environmental impact of their farms,” said Lowry Harper, president of Harper Consulting, who conducted the study from decades-long data.

The study, funded by the Pork Checkoff and conducted by Harper Consulting in consultation with Southern Utah University, found that North Carolina pig farmers have significantly increased feed efficiency over the past 17 years. Long-term, continuous improvement has resulted in trending reductions in nutrient content in manure lagoons at the farms. Specifically, data gathered from more than 106,000 samples at the 182 participating North Carolina pig farms showed a reduction of 35% to 78% in the nutrient content from hog finishers in primary lagoons, and a reduction of 17% to 68% in primary lagoons for sow farms. Also, the study showed a reduction of 22% to 54% in ammonia levels.

The analysis showed considerable improvements in pig farms’ nutrient output, with major decreases in all nutrient concentrations, except for copper which is an essential dietary nutrient. The modeling conducted suggested decreased emissions, including ammonia.

While the study looked at North Carolina farms, the findings can likely be replicated throughout the country as U.S. pig farmers adopt better genetics and target nutrition and greater veterinary care.

The environmental study shows hog farms’ contributions to nutrient levels and ammonia emissions have declined significantly over the last two decades. Other activity – increasing human population and growth in associated emission sources like automobiles, industry and human waste processing – has likely contributed to a general increase in ammonia emissions in the state.

The study also found that “advancements in swine production practices, changes in feed formulation, improved swine genetics, reduced nutrient excretion and other management changes have resulted in reduced nutrients in both primary and secondary lagoons.”

“U.S. pig farmers have a great story of sustainability to share, and this study validates it,” said Jan Archer, a pig farmer from Goldsboro, North Carolina. “Farmers have always been good stewards of the environment, and we are proud of the continuous improvement and innovative practices on our farms. As a pig farmer in the second-largest pork producing state in the country, I am proud of our record and believe these sustainability gains are being replicated by many of my fellow farmers in other states.”

A research summary of the environmental study is here and also online at pork.org.

Related Stories
Record Choice grading levels are changing how beef quality premiums are valued.
Colorado Congressman Jeff Hurd joins Champions of Rural America to share insights into the Western Caucus legislative priorities as they champion wildfire prevention and mitigation in the West.
The closure of Lubbock Feeders highlights mounting pressure on the U.S. cattle supply, according to the Texas Cattle Feeders Association, as border restrictions and costs strain feedyards.
NCBA Chief Counsel Mary-Thomas Hart discussed the legal process behind delisting the prairie chicken, the challenges ranchers faced under the bird’s previous protections, and the benefits of cooperative habitat management for both livestock and wildlife.
Food demand is stable but price-sensitive across rural markets. For agriculture and rural communities, the important signal is not optimism — it is stability.
Stable blending demand continues to underpin corn use despite export volatility.

LATEST STORIES BY THIS AUTHOR:

Farm legal expert Roger McEowen discusses the EPA’s rescission of the 2009 endangerment finding on greenhouse gases and what it could mean for agriculture and rural America.
Chef and influencer Marcia Smart joined us to discuss Italian-inspired beef dishes, nutrition for active lifestyles, and how global events shape home cooking.
The USDA says the framework is about “ending abusive government overreach” and “protecting farmers, families, and private property.”
Farm numbers still favor small operations, but production, resilience, and risk management are increasingly concentrated among fewer, larger farms.
Wed, 2/18/26 – 7:30 PM ET
Agriculture Shows
Hosted by Scott “The Cow Guy” Shellady and RFD News Markets Specialist Tony St. James, Commodity Talk delivers expert insight into the day’s ag commodity markets just before the CME opens. Only on RFD-TV and Rural Radio SiriusXM Channel 147.
A look at the news, weather and commodities headlines that drove agriculture markets in the past week.
Everything profits from prairie. Soil, air, water — and all kinds of life! Learn how you can improve your land with prairie restoration, cover crops and prairie strips, while growing your bottom line.
Special 3-part series tells the story of the Claas family’s legacy, which changed agriculture forever.