COLLEGE STATION — The heifers graze contentedly surrounded by electrical wire and horizontal rows of PVC pipe about 15 feet high. Pump motors hum steadily in the background as methane from the heifers is collected into the pipe. A video camera on a deer stand monitors their every move. Other equipment collects every type of weather data imaginable.
Dr. Floyd M. Byers, an animal nutritionist with the Department of Animal Science at Texas A&M University, is in a nearby trailer staring at a computer screen. “You see that differential there?” he asks another man sitting nearby. “They must be awful close to the fence.”
They quickly look out the window. “Yes, they are,” says Dr. Ron Sharpe of Watkinsville, Georgia, research soil scientist with the Agriculture Research Service section of the U.S. Department of Agriculture. Little do the heifers know they are part of a cooperative project between Texas A&M University and the U.S. Department of Agriculture that is studying the effect of methane on the global climate change and on the efficiency of cattle feeds.
Studying methane emissions from cows may cause snickers in some circles. But Byers, who unapologetically tells visitors he received the Bum Steer award from Texas Monthly magazine several years ago for his cattle methane studies, takes his work very seriously.
“Methane is a direct energy loss from cattle,” Byers explains. “We want the animal to capture more of the energy from the forage.” As much as 25 percent of the energy in feed is wasted through methane emissions, and the focus of his project is to find out what cattle eat that gives them gas.
In the past, animal agriculture has often focused on reproduction as the means to increase efficiency. That has shifted now, he says, to extracting the most energy from the feed and the digestive tract. He hopes to devise feeding systems that optimize the digestive process and reduce animal waste. Less waste means less disposal problems.
The second goal of the project is to study the role of methane in global warming. Presently, the natural abundance of methane is 1.7 parts per million (ppm), and it is rising at a rate of 1 percent per year. Byers points out, however, animal production only contributes about 10 percent of the 550 million metric tons of methane produced annually.
The enclosure, which is 80 feet by 80 feet, was developed by ARS scientists in Georgia. Sharpe’s interest in the project lies in how this can help them measure methane production from chemical and natural fertilizers on crops, as well as production from animal waste lagoons.
Inside the enclosure, any methane the cattle emit is collected into capillary tubes on 16 lines placed four deep on each side of the enclosure. This allows the scientists to study the amount of methane at different levels and make sure none escapes. Samples from each tube travel to a laser in the mobile trailer. There, the density of the methane sample is measured.
The laser, only one of six of its kind in the world, allows the scientists to measure the concentration of methane in parts per billion, one thousand times smaller than the natural occurrence, Byers says.
Weather data, such as wind speed and direction, air temperature, and solar radiation, also are taken in order to determine their effect on the methane levels.
Previously, data such as this would have to be taken in an enclosure made of a solid material, such as glass. “In those, the cattle are not grazing, eating, ruminating, or chewing like they normally would. That left us with the question as to whether these types of chambers were applicable to the real world.”
Byers hopes his analysis of the data collected will be complete by the end of the year.