On a typical drive through southern Wisconsin, travelers can watch cows grazing peacefully on farm-speckled landscapes. Many find this to be a truly relaxing scene, until the smell of manure sets in and the passengers begin gagging in their stifled cars that now smell like the inside of a barn.
But people may be breathing easier soon, thanks to research being performed by a UW-Madison student who is working to take some of the stinky smell out of manure, something all Wisconsin residents can appreciate.
Tanya Dunlap, a student working on a Ph.D. in nutritional science, is conducting research at the Dairy Cattle Center on campus. She is attempting to shift nitrogen levels from the animals’ urine to feces, possibly resulting in cleaner air, and increased fertilizer value for plants.
Working under a fellowship from the Environmental Protection Agency, Dunlap is experimenting with different feeds in order to study the possible nitrogen-level change. Dunlap’s two-month long experiment consisted of four feeding shifts per day, one of them at 3 a.m.
“I’ve learned to sleep sporadically,” she said.
Dunlap claimed that shifting nitrogen into the feces makes it more difficult to break chemical bonds to release it into the air, and more plants consume the particles in order to grow. Therefore, it should decrease the amount of nitrogen available, making lumps of manure healthier for the environment, she said.
Dunlap experimented with four cows that each contain a fistula, or an opening in the side of a cow wide enough for an entire human arm to enter into any of the four stomach chambers.
She was able to give each cow different treatments of pectin, a dietary fiber, and uses the fistula to bypass the first three stomachs and put the pectin directly into the fourth — the abomasum — in order to observe how much bacteria fermentation takes place in the colon.
“By stimulating fermentation in the colon, I am able to see if we could shift the levels of nitrogen from the urine into the feces,” said Dunlap, who received her undergrad and masters degrees at the University of Maryland.
Increasing fermentation in the colon provides bacteria the chance to consume nitrogen to grow, meaning that less nitrogen will be in the cow’s body and able to escape into the urine. Excess nitrogen not consumed by bacteria will then be excreted in the feces, Dunlap said.
Most of the nitrogen, which was converted from ammonia in the cow’s liver, leaves the body in the form of urine. This nitrogen is then released into the air.
When it escapes into the air, it is immediately converted back to ammonia, which is what gives manure its notoriously bad smell. This chemical can travel back down to earth in the form of acid rain, or it can bind with sulfur dioxide (a chemical produced by car exhaust and industrial plants), a major contributor to air pollution.
Dunlap has just finished collecting urine and fecal samples and will spend the duration of her research studying their chemical levels.
When asked if the transfer of higher nitrogen levels into manure could lead to increased groundwater pollution, Dunlap claimed this form is better for the environment.
“Everything has a negative effect, but it is much more agronomical to have nitrogen in the manure,” she said.
It is more difficult to break down nitrogen in manure, so the leaching problem is not as serious, and plants like this form because they need nitrogen to grow so there will be less groundwater runoff, she said.
Dunlap acknowledges this research is not realistic for an average dairy farmer to use, but it is an important stepping stone in determining a diet for cows that can be both nutritional and environmentally friendly.
“This is not practical in any way, and technically no one on a farm would do this,” Dunlap said. “We will use these results to predict levels of fermentation and incorporate these diets with cows in order to have positive environmental results.”
Jerry Guenther, assistant herdsman at the Dairy Cattle Center, said having the facility on campus allows students like Dunlap to be able to conduct research close to home.
“Animals are close to buildings so researchers and graduate students can be there to work with the cattle around the clock,” he said. “And they can immediately take samples across the street to the lab for analysis.”
The Center is not only accessible to Dunlap and four other researchers currently using the facility, but offers employment to undergraduates as well.
Sally Flis, a UW senior majoring in dairy science, is one of 12 students the center employs.
“We get to see research taking place, which has motivated me to continue my career here to conduct research as well,” Flis said.
The Dairy Cattle Center has also benefited farmers by allowing them to learn about research breakthroughs. The living farm on campus provides farmers with techniques of advanced breeding methods and then enables them to apply these methods to their own operations, Guenther said.
Could Dunlap’s research make traveling in the Wisconsin countryside less nauseating?
“Yes,” laughed Dunlap, “It should improve odor because it reduces the amount of ammonia in the manure, which is what gives it its smell.”
