The Food and Agriculture Organizations of the United Nations (FOA) estimates that providing a 5 year old with a glass of milk each day also provides this child with 21% of the daily protein and 8% of the daily calories needed by the child. Furthermore, milk provides key nutrients such as calcium, magnesium, selenium, riboflavin, vitamin B12 and vitamin B5. With cattle providing 85 % of the world’s milk it is also important to understand how these animals are fed and to know that dairy cattle are very effective in producing high quality and nutritious foods from feedstuffs that are also largely inedible by the human population. The key link and ability for these animals in consuming these feeds are the thousands of microbes that reside in the rumen. Currently, in the Department of Animal Science at the University of Nebraska-Lincoln Drs. Samodha Fernando and I are discovering how the diet fed to dairy cattle affects the rumen microbes that are responsibility for digesting many of the nutrients that a cow consumes each day.
Recently our collaboration has focused on methane production by cattle. It is important to study methane because agriculture contributes approximately 7% of the total U.S. greenhouse gas emissions and methane from microbial fermentation represents 20% of the total methane emitted. This methane production also represents a key loss of energy from both the rumen microbes due to feedstuffs and cows. Therefore, finding ways to reduce methane production by rumen microbes should improve sustainability and production.
Several years ago I had a graduate student observe that feeding cows distillers grains actually improved milk production and also resulted in cows producing less methane. For use to understand why this may be happening we have two projects underway. One is funded by the Nebraska Environmental Trust and the other funded by the Nebraska Corn Board. The overarching objective of these projects is to develop science-based dietary intervention strategies to reduce greenhouse gas emissions from methane production in dairy cattle production systems. To this end, these projects investigate the rumen microbial community under different dietary treatments to identify and characterize the complex microbial community and members of the microbial community that influences methane emission. Additionally, these projects simultaneously monitor animal performance – including milk production - and methane emissions.
To conduct these studies we used lactating Jersey cows and collected total gas production in a controlled environment. The device use to do this is called an indirect calorimeter. This device allows us to know example how much oxygen a cow is consuming and how much methane is produced in her rumen. As you can imagine this work keeps us busy around the clock with cows under continuous observation. These projects are scheduled to be completed this spring, and it will be our aim to share how producers can reduce methane emission from cattle and use the energy saved by reducing methane emissions to use for milk production. We will use the information from these projects will deliver science-based knowledge and informal educational programs to dairy producers through producer friendly extension curricula, which will provide dairy producers with the resources and information they need to make changes to their feeding and production systems.