Bovine genetics can impact carbon emissions

Bovine genetics can impact carbon emissions

For decades, the beef industry has studied the role genetics play in cattle performance. This research has enabled beef producers to utilize expected offspring differences (EPDs), leveraging inherited traits to produce animals that excel in their particular environment and management style. New cooperative research between the American Hereford Association and Colorado State University (CSU) is underway to identify genetic components associated with environmental sustainability in beef cattle.

Some people believe that ruminants have a negative impact on the environment and contribute to global warming due to their production of methane. Methane (CH4) is produced by rumen microbes during the digestion of fibrous plant matter. The Environmental Protection Agency estimates that 11% of greenhouse gas (GHG) emissions in the United States come from the agricultural sector. According to Frank Mitloehner, a UC Davis professor and air quality specialist, cattle and other ruminants account for 4% of our GHG emissions. Methane is of great concern because it is 25 times more potent than carbon dioxide (CO2) to trap heat in the atmosphere.

Olsen Ranches. Courtesy picture
Olsen Ranches. Courtesy picture

“This industry has done an amazing job producing more beef from fewer cows, but we will continue to be asked to do more with less,” said Jack Ward, executive vice president of the American Hereford Association (AHA). “Over time, we have documented the value of Hereford genetics in commercial cow herds in terms of fertility, longevity, feed efficiency and other traits associated with production efficiency. All of these things, as we currently understand, are going to have a positive effect in terms of sustainability as we progress through the industry.



Identify the genetics linked to environmental sustainability

Specifically, AHA-CSU research aims to improve understanding of genetic differences in seed stocks in relation to enteric methane production and nitrogen excretion.



Are some cattle genetically predisposed to use carbon and nitrogen in feed to build body and muscle mass rather than exhaling or excreting nitrogen and methane? Can we identify those genetics that support environmental sustainability in cattle? These are the questions that researchers are looking into.

In a small study at CSU before the pandemic, Scott Speidel Ph.D. who specializes in animal science, breeding and genetics at CSU, explained that preliminary data showed that nitrogen excretion had a genetic link. . He believes the methane emission will also reveal a genetic component that will lead to the development of breeding tools to reduce the carbon footprint of beef.

Understanding genetic differences in seed stock in relation to enteric methane production and nitrogen excretion and identifying genes that reduce greenhouse gas emissions without sacrificing animal productivity is the task of Kim Stackhouse-Lawson, director of CSU’s AgNext and other CSU researchers in this study.

Snack vending machines

Greenhouse gas emissions from livestock have been studied in previous research at CSU explains Stackhouse-Lawson. In the 1980s, methane emissions were recorded in a room, she says. Recent advances in technology allow research in the natural environment of livestock, which will provide real data since livestock will behave normally.

Cattle from the Olsen Ranches feedlots in Harrisburg, Nebraska, will be studied using bait stations in methane collectors. Portable bait stations or snack dispensers dispense bait, usually alfalfa pellets, into a hopper. When eating a treat, the animal puts its head into the hopper. The oxygen, hydrogen, carbon dioxide and methane exhaled by the animal are measured, conveying information about the animal’s physiology and what is going on in the digestive system.

Cattle, in general, lose about 75 percent of methane through their lungs when they exhale, 15 to 20 percent when belching, and the rest as flatulence and in manure explains Stackhouse-Lawson. Therefore, measuring the amount of methane cattle exhale will give a good indication of how much methane they release into the environment. Most cattle will go to the “snack dispenser” two to four times a day; it takes 30 days of readings to accumulate baseline data on each animal, she notes.

In addition to measuring methane, this study also monitors water consumption, nitrogen and ammonia levels in the manure.

Combine data

With approximately 15 different bull groups at Olsen ranches, the new data, when added to information gathered through the AHA’s Total Herd Performance Records (TPR™) and the National Bull Reference Program, including food intake and efficiency records, will provide detailed information. which can be used in an EPD and eventually evolve into a selection index for environmental sustainability.

Sustainability and methane

Sustainability rests on three pillars: social, environmental and economic, says Stackhouse-Lawson. Without all three, sustainability is not possible. Interestingly, she points out that due to the focus on feed efficiency, cattle that naturally produce less methane may already have been selected. Producing methane, as a result of digestion, results in a loss of energy, she points out. When plant matter is converted into energy by livestock, several studies have shown that 2-12% of the energy in the diet is lost to methane emissions. With reduced methane production, more energy is retained by the individual and used for growth, reproduction, milk production, etc.

Stackhouse-Lawson also claims that the methane produced by livestock is part of the natural or biogenic carbon cycle, unlike the methane and carbon dioxide produced by the manufacturing and burning of fossil fuels and other human-made activities. Plants absorb carbon from the air during photosynthesis, turning it into energy for their growth. Cattle consume the plant and release some of the carbon into the air as methane which will return to the plants. Biogenic methane can stay in the environment for 10-12 years, unlike extra CO2 which is added to the atmosphere with the burning of fossil fuels that remain for a thousand years. This significant difference is rarely highlighted.


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