When it comes to feeding the world, cattle have a starring role. At the same time, they play a part in the emission of methane, one of the three major greenhouse gases. And as we rise to the challenge of feeding a rapidly growing world population (with finite resources) and put our heads together to find a way of doing so sustainably, neither fact can be ignored.

Ph.D. Student / University of California – Davis CLEAR Center

With pressure to cut emissions stronger than ever, there is a large conversation around the best methods to manage cattle. The major question becomes: How do we balance the scale so we can nourish more people and simultaneously lessen the greenhouse gas effect? It’s a dilemma of epic proportions, with pressures that affect ranchers, dairy farmers, the supply chain, consumers and, ultimately, society.

So the drive to advance the stewardship of our land and cattle is widely shared by researchers, ranchers and farmers. Researchers are making breakthroughs all the time, with one of the latest efforts coming from the CLEAR Center at University of California – Davis. Bolstered by funding from the California Department of Food and Agriculture (CDFA) Livestock Enteric Methane Emissions Reduction – Research Program (LEMER-RP), scientists are investigating the novel concept of early-life intervention tactics and execution (ELITE). In other words, we are working with the youngest of animals to increase the tools available for ranchers and dairy farmers to continuously improve the sustainability of their cattle operations and reduce the footprint of meat and dairy products.

Early could be right on time

Cattle are ruminant animals. As such, they have a specialized digestive tract for fermenting plants through microbial activity in their stomachs. These microbes allow cattle to break down cellulose that’s undigestible by nonruminants, including humans, but that superpower also results in fermentation byproducts being released by the animal. This means the microbes produce methane during digestion, which cattle expel in the form of belches as they digest their food.

To combat it, CLEAR Center scientists are using early-life intervention, which entails implementing initiatives and strategies in young animals – in this case, calves. Simply put, researchers are altering microbes in the rumen before they fully develop, hoping to limit methane production from the day the animal is born. Not only does it bode well for the reduction of the potent greenhouse gas, but it also stands to improve long-term animal health, development and welfare, making ranches and dairy farms more sustainable while the environment reaps its own rewards.

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It’s a 180-degree change from the norm. Most of the research around methane-reducing feed additives has focused on mature cattle with fully formed rumens. Plus, the approach requires daily feeding of additives, in some instances multiple times a day, presenting a host of challenges to farmers and ranchers. With early-life intervention, calves get a head start, both on health and on a lifetime of lower methane emissions. It’s as much about cutting greenhouse gases as it is about shaping their futures, starting on day one.

By contrast, reducing greenhouse gas emissions in mature cattle proves a challenge; their fully developed rumens have well-established microbial communities. Methane-reducing feed additives can lower methane production, but they have limited long-term impact on these entrenched microbes. As a matter of fact, research shows that when methane-reducing feed additives stop, rumens return to their original states and methane production reverts to its original levels.

One way to tackle this challenge is by looking at ways to permanently shape the rumen environment in calves, with the goal of reducing greenhouse gas emissions over their lifetimes. Until recently, scientists have disregarded this approach, since calves produce relatively small amounts of methane while their rumens are developing and they’re beginning a diet of solid food. Yet, this early period could be crucial for making a lasting impact.

Getting in on the ground floor

Calves aren’t fully developed ruminants, meaning their rumens, which allow for forage and concentrate breakdown, aren’t capable of digesting solid feed as an adult animal can. In fact, calves are more like pseudo-monogastric than actual ruminants. They’re born with an esophageal groove that allows milk to bypass the first three stomach compartments (rumen, reticulum and omasum) and be delivered directly to the true stomach (abomasum), the only fully functional stomach compartment in newborn calves.

Over time, the four compartments of the stomach develop their functions through exposure to solid feeds. The volume of these compartments begins to shift toward the development of a fully functional ruminant, capable of breaking down concentrates and forages.

Farmers and ranchers know long-term health is impacted by starting calves off in the right direction – colostrum absorption and proper nutritional transitions lay the foundation for a calf’s future. Likewise, as calves are introduced to solid feed, it will influence beneficial bacteria and the compounds they produce. The CLEAR Center team is exploring ways to make the early weeks count even more by shaping gut microbes to reduce emissions down the road.

It’s a small window of opportunity, however, currently estimated at approximately 12 weeks. After roughly three months, calves’ rumens begin functioning like those of mature ruminants, and methane-producing microbes approach mature levels and emit peak methane emissions. At that point, all we can hope to do is mitigate the emissions with treatment.

What we know

Studies focused on early-life diet modification and rumen microbial community alterations in young ruminants show the potential for long-lasting effects on rumen microbial communities. In another recent study, supplementing calves with a methane-reducing feed additive from birth to 14 weeks old resulted in lower long-term emissions, even after the compound was no longer administered. Although further investigation is needed, these results show the feasibility of using early-life intervention strategies to imprint the long-term ruminal environment, leading to a lifelong reduction in greenhouse gas emissions.

Getting to the new rumen

If a calf’s digestive system is built to bypass the developing rumen via the esophageal groove, how can scientists target it? The recent study looking at the effectiveness of giving feed additives to calves for long-term reductions of methane emissions found that administering the additives two hours after bottle-feeding worked well because it avoided the active use of the esophageal groove and allowed the additives to be deposited into the rumen.

Another practical solution is a slow-release calf bolus – a pill of sorts – that could be given once at birth. This pill would gradually release feed additives into the rumen without any further effort needed from the producer. More research is needed to confirm its effectiveness in calves, but signs point to producers being able to efficiently apply feed additives within their operations in ways that would have lasting impacts on methane emissions for the lifetime of these cattle.

What does it mean?

Shrinking livestock’s carbon hoofprint worldwide is a daunting challenge, but given the pivotal role animal-source foods play in nourishment, it’s one that must be addressed. As researchers at the CLEAR Center and other institutions work to give farmers and ranchers an arsenal of effective tools to foster environmental and agricultural sustainability, effective solutions for early-life intervention strategies could make a measurable difference.

Madison Kindberg is a Ph.D. student in Frank Mitloehner’s lab and the CLEAR Center at UC Davis. From Oakdale, California, Kindberg established her own commercial cow-calf operation while still in high school that has now expanded into cattle and hay production.