The effect of changing dairy-cattle diets to reduce methane production recently was studied at the University of Wisconsin-Madison Dairy Science Department. Elias Uddin, who is pursuing a doctorate at UW-Madison, recently shared results of the study with dairy producers at the PDPW Business Conference, held March 14-15 in Madison, Wisconsin.
The dairy industry contributes only about 2.5 percent of total greenhouse-gas emissions in the United States. But even those emissions could be further reduced through genetic and nutritional approaches that are relatively simple and easy to implement, Uddin said.
“Research has established that both type and source of carbohydrate – fiber or starch – in a dairy cow’s diet have a substantial impact on enteric methane,” Uddin said. “That might also affect greenhouse-gas emissions from manure because we know that fiber – neutral-detergent fiber – level and source can affect digestibility of nutrients and chemical composition of manure.”
Working with Michel Wattiaux, professor of dairy-systems management at UW-Madison – Uddin also studied the effect dairy breed might have on emissions. The researchers studied how fiber source and fiber level affect lactation performance, feed efficiency, energy and nitrogen utilization efficiencies of Jersey and Holstein cows. The researchers also studied the cows’ enteric-methane emissions and manure greenhouse-gas emissions – during storage and after application to soil.
Compared to the Jersey cows, the Holsteins studied consumed more feed and produced greater amounts of milk, fat, protein, and fat- and protein-corrected milk. But the Holsteins produced lower percentages of milk fat and protein while producing more methane per day.
Cows fed lesser amounts of forage neutral-detergent fiber performed better. But researchers said they were surprised that those animals emitted more methane than cows fed higher levels of forage neutral-detergent fiber.
Another one of the research findings is that cows fed higher levels of corn silage performed better and emitted less methane per dry-matter intake. They also emitted less methane per forage nutrient-detergent fiber than cows fed higher levels of alfalfa silage.
The impact of breed as well as level and source of neutral-detergent fiber from forage on efficiencies depended on the mode of calculation, the researchers said.
“Like other businesses, the dairy business must be sustainable,” Uddin said. “We’re focusing on the economic and environmental aspects of sustainability. Our goal is to perform a life-cycle analysis based on whole-farm emissions to calculate the carbon footprint of milk for different dietary approaches.”
From that analysis researchers expect to determine which approach is better in terms of both farm profitability and environmental soundness, Uddin said.
Uddin was born and raised on a crop and livestock farm in central Bangladesh. His bachelor’s degree is in animal husbandry. He earned a master’s degree in animal breeding and genetics jointly from Wageningen University and Research in the Netherlands, and the Norwegian University of Life Sciences. He said he particularly enjoyed dairy science and decided that pursuing a doctorate in that area might be the best fit for his career. He decided to pursue his doctorate at UW-Madison.
“The UW-Madison Dairy Science graduate program is considered the best program in the world,” he said. “It has world-renowned faculty, and dynamic and modern technologies and facilities for conducting research.”
Lynn Grooms writes about the diversity of agriculture, including the industry’s newest ideas, research and technologies as a staff reporter for Agri-View based in Wisconsin. Email firstname.lastname@example.org to contact her.