Cows Shouldn’t Get a Bum Rap, Researcher Says

In a towering beige barn on the outskirts of the UC Davis campus, Frank Mitloehner explained the finer points of his current field of scientific inquiry: cow flatulence.

Mitloehner, a plain-spoken native of Goettingen, Germany, who could pass for a dairy farmer in his crisp denim shirt and blue jeans, has emerged as an outspoken contrarian voice on an issue of great importance to the San Joaquin Valley: How much do cows pollute?

The San Joaquin Valley is home to the biggest single segment of the nation’s dairy industry as well as the country’s smoggiest air. The San Joaquin Valley Air Pollution Control District, prodded by a state law, is preparing to tackle the problem with tough new regulations on factory dairies.

This week, in a preliminary step, district officials estimated that cows emit more of a key smog-forming ingredient than cars. It is a controversial claim.

Mitloehner, whose research helped form the basis of the cow-pollution estimate, argues that the officials misused his findings. In a series of temperature-controlled environments in Davis that mimic the various aspects of a real factory dairy, Mitloehner has spent much of the last two years measuring cows’ gaseous emissions in meticulous detail.

“I have this deep love of animals and the way they interact with their environment, so I knew I wanted to end up in this field,” Mitloehner, 36, said during a tour of his research facilities last week. “But I had no idea it would be so controversial.

“Sometimes, I think everything in California is controversial,” he added with a smile.

Mitloehner’s first surprise was how much of the pollution comes from the front end of the cow and not from the malodorous piles of waste they produce.

His conclusion that most of the offending gas comes from the cow’s chewing and regurgitating runs counter to the prevailing theory, which had earned such research the derisive label “fart science.”

But the pollution from cows’ digestive process remains poorly understood, Mitloehner said. He argues that more research is needed before assigning so much blame for San Joaquin Valley smog to ruminating cows and before imposing tight restrictions hastily.

Until he did his fieldwork, California’s official estimate of bovine air pollution was based on an extrapolation from a 1938 New Hampshire study.

Mitloehner had openly scorned officials’ application of the study to modern California dairies and testified at county government meetings. To hammer home his criticism, he likes to show visitors a weathered brown copy of the study. It is an antiquated-looking document that contains charts comparing emissions from cows and elephants.

Some environmentalists assert that by siding with the dairy industry and criticizing other scientists’ work, Mitloehner has jumped over an ethical line scientists should not cross.

“He has a history of taking positions on this issue. Meanwhile, his research is relevant to the way this issue is playing out,” said Brent Newell, an attorney with the Center for Race, Poverty & the Environment, a group that has pushed for stronger pollution regulations on dairies.

“He is crossing a line from scientist to subjective advocate. It’s his job to do his research, not opine on the district’s use of other studies,” Newell said.

Mitloehner, whose studies are funded by state and federal environmental agencies, rejects that assertion.

The same groups that question his motives would be championing his views and commending him for courageously taking a stand if he agreed with them, he said.

San Joaquin air quality officials on Monday officially estimated that the average dairy cow releases 19.3 pounds of pollutants known as volatile organic compounds every year. Volatile organic compounds react with another type of air pollutants, nitrogen oxides, to form ground-level ozone, or smog.

A sizable chunk of that estimate, 8.3 pounds, is based on measurements of gases known as volatile fatty acids that Mitloehner considers imprecise. He said he submitted the data with a stern caveat that it was too uncertain to be used in regulations.

Air pollution officials slightly lowered their initial estimate of 20.6 pounds of pollution per cow to the 19.3 number in response to some of Mitloehner’s criticisms but still based much of their estimate on the data he considered unfit for rulemaking.

“The one piece I said to them could not be used for regulatory purposes is what they used,” he said. “They concluded that they knew my data better than I did.”

David L. Crow, the air pollution control district’s executive officer, stood by his agency’s conclusions, which he said were based on 15 scientific studies examining various aspects of cow emissions, including the gases emanating from cow waste at various stages of the factory dairy process.

“One of the important things to understand is that we were looking at all the potential emissions sources on a dairy, and no single scientist has looked at all of that,” Crow said.

Mitloehner said he recognizes that factory dairies will have to be strictly regulated. For example, he believes ammonia from cow waste, which produces fine-particle pollution that has been linked to respiratory problems, may also need to be curtailed. San Joaquin pollution officials chose not to pass ammonia limits on dairies, unlike their counterparts at the South Coast Air Quality Management District, which includes Los Angeles and Orange counties and parts of Riverside and San Bernardino counties.

But he argued that regulators have a lot of work to do before they can fully understand the best ways to reduce emissions from dairy cows. Some pollution, he contends, may be unavoidable.

“The people of this state enjoy the commodities of agriculture: the wine, the cheese, the fruit,” Mitloehner said. “But these things come with environmental consequences. The issue is how much are people willing to take.”

*

(BEGIN TEXT OF INFOBOX)

On the move

While most young Germans went to universities in the west half of the country after the fall of the Berlin Wall, Mitloehner went east, to the University of Leipzig. “I was never a conformer,” he said.

* Mitloehner’s animal science work has taken him to China, Australia, Paraguay, South Africa, Namibia, Botswana and Indonesia. He met his wife, Elizabeth, a grants director at UC Davis, a month after moving to California.

* Mitloehner, who did his postdoctoral research at Texas Tech University, was once asked to study why cows kicked up more dust at night. The answer: they were hungry and restless.

Los Angeles Times