Sizing up Pork Production’s Energy Use

October 13, 2010 — 

Iowa State University researchers have used the life-cycle assessment concept to estimate the nonrenewable energy needed to produce pigs in Iowa. A two-year grant from Iowa State's Leopold Center for Sustainable Agriculture and a USDA Sustainable Agriculture Research and Education grant funded the project.

The concept of "life-cycle assessment" was first applied to manufacturing processes but is increasingly used to examine agriculture today. The technique analyzes the environmental impacts associated with a product, process or service.

The Iowa State research took into account all direct and indirect energy inputs used for the construction and operation of a swine production facility, as well as for growing and processing feed ingredients. Researchers compared a conventional-confinement system with mechanical ventilation and liquid-manure handling, and one that uses bedded hoop barns for grow/finish pigs and gestating sows.

The two housing systems required similar amounts of nonrenewable energy, but each used energy differently says Pete Lammers, a former Iowa State doctoral candidate in animal science. Lammers is now a livestock specialist for the National Center for Appropriate Technology in Des Moines.

He points out that raising pigs in conventional-confinement facilities requires more energy to heat and ventilate the buildings. "Using bedded hoop barns for gestation and grow/finish reduces this energy use by almost 70 percent," he adds.

However, pigs raised in hoop barns require more feed, which ultimately equals out the energy use between the two systems. "Earlier Iowa State research showed a hoop barn-based system requires 2.4 percent more feed. In addition, the nitrogen value in the solid manure is less than what's available in liquid manure from a confinement facility. That means more fertilizer nitrogen must be applied to corn fields," Lammers notes.

The researchers found that growing the feed is the largest single use of nonrenewable energy in pig production. Approximately 50 percent of the nonrenewable energy associated with growing and processing a typical corn/soybean meal diet can be attributed to synthetic nitrogen fertilizer for corn production.

So although conventional facilities require more energy to operate fans, lights and heaters, the energy related to crop production is slightly less than for hoop barn production.

Mark Honeyman, animal science professor and coordinator of Iowa State's research farms, says the research showed there's been a huge drop in nonrenewable energy use in pork production over the past 35 years.

"The study showed nearly an 80 percent reduction in nonrenewable energy use to produce one market pig in Iowa today, compared to 1975, which was the last time this topic was examined," Honeyman notes. "This can be attributed to improved genetics and nutrition, changes in housing and ventilation systems and overall production efficiency gains."

Honeyman notes that the research shows the key to further reducing nonrenewable energy use is nitrogen management. "Strategies to optimize nitrogen stocks and flows among crops, livestock, manure and soil should be a priority for future research," he adds.

Source:
Pork Magazine
By Pork news staff | Wednesday, October 06, 2010
http://www.porkmag.com/news_editorial.asp?pgID=675&ed_id=9994&news_id=25695&ts=nl2