Sustainability starts in the microbiome

Part 1: Cows and climate change
When Canada’s beef industry says its priority objective is to be sustainable, what does that mean, specifically?

The answer isn’t a simple as you might think. A comprehensive definition should include animal health, eating quality, the impact of production on the environment and the ecosystem services returned to Canadians, stewardship of the land, and the circular economy that includes the ability of cattle to use byproducts as feed and the production of energy from manure.

“The short answer,” says Tim McAllister, Principal Research Scientist for Agriculture and Agri-Food Canada in Lethbridge, Alberta, “is that we have to take a systems approach to sustainability.”

McAllister’s research focuses on cow microbiology, nutrition and biology, and how their influence on sustainability depends on their interaction with the rest of the cow. This isn’t simple, either. Interaction could refer to the microbiome of the respiratory tract and the cow’s likelihood of developing pneumonia that needs treatment with antibiotics. Or it could be the microbiome of the digestive tract and the cow’s resulting feed efficiency and methane production, the likelihood of digestive disturbances, or the influence the microbiome has on establishing human pathogens within the cow’s digestive tract, which can even influence the amount of methane produced from biodigested manure.

McAllister is collaborating with Gentec researcher Leluo Guan on the two-way communication between these microbiomes and the cow.

“The microbiome is heavily controlled by the immune system and the metabolic end products that the microbes produce. Since proteins and vitamins play a key role in immune response, we’re looking at the nutritional elements of the cow’s diet, especially since, in feedlots, cows are fed byproduct feed, such as distillers’ grains, that would be a liability to the ethanol industry without a market for them as feed.”

The microbiome allows cattle to ferment forages, which results in methane as a byproduct. McAllister points out that the origin of this methane is different than that of methane that is used to heat our homes. Carbon in cow methane comes from the forages it has just eaten, and it has just been captured by the plant through photosynthesis. In most cases, this carbon was carbon dioxide in the atmosphere less than a year before capture.

“So carbon in methane from cattle originates from short-term carbon in the atmosphere as CO2, the season before the animal grazed the plant” he says. “That’s very different from the carbon from fossil fuels. That methane was deposited and stored millions of years ago. Most of it is ancient carbon.”

McAllister points out that cattle and other ruminants were producing methane long before the Industrial Revolution without any significant consequence for climate change. There were 30-60 million buffalo roaming North America’s Great Plains—all far less efficient as they consumed only forages, unlike the forage/grain system used to produce cattle today. Therefore, climate change is really a consequence of the release of ancient—not short term—carbon into the atmosphere. While the methane molecules from these two sources are the same, their origin is vastly different.

Another component is the native and tame grasslands that are managed by Canada’s cow-calf producers. These lands store vast amounts of carbon that would be released into the atmosphere if they were to be cultivated. Using these lands as pasture preserves the land and its biodiversity, with the added benefit of carbon storage.

“Consumers need to understand the nuances associated with beef production in Canada and the roll beef cows play in nutrient recycling,” says McAllister.

Indeed, one of the major issues of the day is food waste. The world actually produces more than enough food for its population but loses over half through poor storage and distribution before it even reaches consumers. In Canada, 30-50% of some foods can end up in composting facilities or landfills—this is after the fuel, fertilizer and transportation energy has been spent to produce it. Once it enters a landfill, there is a good chance it will produce methane during decomposition.

“If we could line up supply channels, food waste doesn’t have to be a net liability,” says McAllister. “Unlike poultry and pigs, which have defined nutritional requirements and a narrow profile for adjusting it, cows live in an outdoor environment and have to deal with a range of forages and feed types. The rumen microbiome is capable of breaking down many different types of toxins, making cattle the logical end user of food waste streams.”

On that note, we’re going to leave you with that cliff-hanger. Next month’s article will continue the story on McAllister’s vision for cutting food waste.