By Galen Erickson
It is not easy to mitigate production of methane from dairy and beef cattle. The rumen of dairy and beef cattle are populated with billions of microbes that digest feed that the animal eats. One of the by-products of rumen digestion is methane. Methane is produced by microbes called methanogens. It is known that methanogens produce methane and that the process of making methane in the rumen is important for the efficiency of the animal. Methane produced in the rumen is belched out of the mouth of cattle and enters the atmosphere. Methane is a greenhouse gas that traps heat on the surface of the earth. Methane accounts for 11.2% of the earth’s atmosphere and 25% of that comes from cattle. Methane has a short half-life of 9 to 12 years; compared to other greenhouse gases like carbon dioxide that have a half-life of thousands of years. After 9 to 12 years, half of the methane produced today is broken down by natural processes. Because methane has a short half-life, reducing methane can reduce the overall greenhouse effect.
Feeding strategies to reduce methane production in cattle are limited, but more research is being conducted. Feeding high grain diets results in less methane production. Adding fat to the diet of beef cattle reduces methane production. Methane production decreased 5.6% for every 1% increase in added fat. Inclusion of fat in rations has limits. Greater than 4% added fat in a ration resulted in a reduction in animal performance.
There are feed additives that reduce methane production in cattle. The feed additive 3-nitriixypropanol (3-NOP named Bovaer and marketed in the U.S. by Elanco) is not approved to be fed to beef cattle but is approved to be fed to dairy cattle in the U.S. 3-NOP reduces methane production when fed to cattle. In dairy cattle, 3-NOP decreases methane production by 30% or even more but the extent of reduction also likely depends on the ration fed. Research in Canada using a GreenFeed system to measure methane showed that when 3-NOP was fed to finishing beef cattle, gain to feed increased 2.5%, dry matter intake decreased by 2.5%, and methane production decreased by 26%.
Feeding seaweed as a method to reduce methane production is also being researched. Bromoform, the active compound in seaweed, disrupts the enzymatic pathway of methane production in methanogens. Although data would suggest a 63% reduction in methane, there are unanswered questions that require further research. Seaweed is challenging to grow in commercial environments, and it is not currently approved to be fed to beef cattle.
Genetic selection to reduce methane production in cattle is possible. Methane production from beef cattle has been reported to be moderately heritable, which is similar to many growth traits. Consequently, methane production would respond to selection. However, before wide-spread genetic selection could occur, selection tools such as EPD would need to be developed which requires a substantial effort in collecting methane data from large numbers of animals. Moreover, the genetic relationship between methane and traits of economic importance would need to be determined to ensure that producers do not unintentionally erode progress made in other traits when selecting for reduced methane.
Source : unl.edu