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LinkedInPosts Tagged: Ermias Kebreab
Grape seeds, stems and skins can reduce dairy cattle emissions
Low-cost wine industry additive also improved feed efficiency and milk quality
Researchers at University of California, Davis, added fresh grape pomace left over from winemaking operations to alfalfa-based feed for dairy cows and found that methane emissions were reduced by 10% to 11%.
The preliminary findings could offer a low-cost sustainable pathway for vineyards to reduce waste while helping dairy operations maintain quality while cutting back on emissions of methane, which is a powerful greenhouse gas.
“This is the first time anybody has shown that this can work in California,” said Ermias Kebreab, an animal science professor and associate dean of global engagement at UC Davis. “You're reducing emissions, you're improving the quality and it may also reduce the cost of production.”
The pilot research project, which will be detailed in a paper later this year, also found that mixing in grape pomace improved feed efficiency and increased healthful fats, said Selina Wang, an associate professor of Cooperative Extension in small scale fruit and vegetable processing.
“We found that the feed with the additive of grape pomace changed the fatty acid composition of the milk and, in particular, increased the polyunsaturated fats, which are the main fats in grape pomace,” Wang said. “This suggests that supplementing the feed with an optimal fatty acid profile may have positive impact on the fatty acid profile of the milk and increase their health benefits.”
Symbiotic commodities?
In 2022, California was the leading dairy producer in the country, generating $10.40 billion in sales, while 90% of wine production came from the Golden State, with a market value of $5.54 billion.
Processing grapes for wine generates thousands of tons of waste in the form of grape pomace, which consists of leftover seeds, skins and stems. Dairy and livestock are responsible for more than half of the state's methane emissions, owed largely to cow burps.
They are the top two agricultural commodities in California, according to state production statistics, and reducing waste and emissions for both industries are key to the state meeting its climate goals.
Tannins for emission reductions
Wine grapes are high in fats and tannin, which is known to reduce methane emissions, so Kebreab sought to test if adding grape pomace to feed could have a positive effect while not adversely affecting production.
“It's a byproduct that's not being used much,” he said. “This is something that can be included in our efforts to try to reduce emissions.”
A mix of feed options
To do the research, scientists worked with Holstein dairy cows and gave the animals feed consisting of alfalfa, wheat, almond hulls, cottonseed and grain. After two weeks, the cows were split into three groups: A control group with no change in diet, another where the feed combination included 10% grape pomace and a third that received 15% grape pomace.
Every four weeks, the cow groups would change feed combinations.
They were fed twice daily by postdoctoral students and interns, and emissions were monitored daily. Milk production was documented in the morning and evening and milk samples were collected weekly to analyze for fat, protein, lactose and other measurements, which showed no differences between the control and other groups.
Methane and hydrogen emissions were reduced compared with the control group, suggesting that grape pomace reduced enteric emissions without affecting production.
“I think the dairy industry will be very interested in this,” Kebreab said. “Sometimes when you're using additives, they have palatability issues. With grape pomace, they absolutely love it.”
Next on the list is a trial with olive pomace and working to understand the mechanism that reduces emissions. “If we have a better understanding of the mechanisms, we can select the feed additive or a mix of feed additives to reduce dairy cattle emissions and make dairy milk healthier while making use of the agriculture byproducts,” Wang said. “There's a lot of room to grow in this space and we're excited about this work.”
The research was supported by the California Dairy Research Foundation.
This article was first published on the UC Davis news site.
Report: California on path to significant dairy methane reduction
Researchers say dairy farms on track to achieve full 40% reduction goal by 2030
The California Dairy Research Foundation and University of California, Davis CLEAR Center announced on Dec. 14 the release of a new analysis of methane reduction progress titled "Meeting the Call: How California is Pioneering a Pathway to Significant Dairy Sector Methane Reduction." The paper, authored by researchers at UC Davis affiliated with UC Agriculture and Natural Resources, concludes that efforts are on track to achieve the state's world-leading target for reducing dairy methane emissions by 40% by 2030.
The report, written by distinguished professors of livestock emissions and agricultural economics, takes a comprehensive look at progress and projections, expanding upon the analysis of progress previously conducted by the California Air Resources Board. By documenting achievements to date, additional reduction efforts already funded, historic and current economic trends, and the projected availability of new solutions, the analysis lays out a workable path toward meeting California's goal. The pathway shows that California dairy farms are on track to achieve the full 40% dairy methane reduction goal and will reach “climate neutrality” by 2030. Climate neutrality is the point in which no additional warming is added to the atmosphere.
“This analysis shows that California's dairy sector is well on its way to achieving the target that was established by SB 1383 in 2016,” said CDRF's Executive Director Denise Mullinax. “With much important work still ahead, a clear understanding of this pathway helps dairy farmers, policy makers, researchers, and other partners make decisions to strategically press forward.”
The report outlines the need for continued implementation of California's four-part strategy for dairy methane reduction: farm efficiency and herd attrition, methane avoidance (alternative manure management), methane capture and utilization (digesters), and enteric methane reduction. Continued alignment of state and federal climate-smart agricultural approaches and incentives will also be critical to maintaining progress.
"Milk demand is growing, and California is among the world's low-cost suppliers of dairy products. It follows that effective California policy to reduce dairy greenhouse gas emissions must recognize that measures that cause milk production to exit the state do not mitigate global climate change," said study co-author Daniel Sumner, Distinguished Professor in the Department of Agriculture and Resource Economics at UC Davis. "Therefore, measures to help off-set mitigation costs, provide positive incentives for adoption of low-cost emission-reducing practices, and help stimulate innovation in methane reduction, are the economically efficient approaches."
The paper recognizes that enteric methane from the dairy and other livestock sectors is a significant source of greenhouse gas emissions in the U.S. and California. Several feed additives are expected to become commercially available in the next several years, which could be used to reduce enteric methane emissions from California's dairy herd.
“Adoption of enteric feed additives will become a valuable tool for dairy value chains to meet their greenhouse gas reduction goals,” said co-author and professor Ermias Kebreab, associate dean of global engagement and director of the World Food Center at UC Davis. “While this report provides only a broad overview of some of the most promising solutions, there is an incredible amount of research being conducted at UC Davis, nationally and internationally. The dairy industry, global food companies, state and federal agencies, and others continue to invest heavily in supporting enteric mitigation research efforts.”
The report finds that methane reductions from California's programs and projects in place today, coupled with the implementation of a moderate feed additive strategy to reduce enteric emissions, is on track to reduce between 7.61 to 10.59 million metric tons of methane (CO2e) by 2030, all from the dairy sector alone.
The collective investment in California's dairy methane reduction effort — from public and private funding — now exceeds $2 billion and counting. The California dairy sector, in coordination with the California Department of Food and Agriculture, was recently awarded up to $85 million by the United States Department of Agriculture under the Partnerships for Climate-Smart Commodities. The funding will leverage additional matching state funds and private capital investments, for a total of more than $300 million in new investment.
“It is important to highlight California's investments and success to date as an example of what is possible within the global livestock sector,” said co-author Frank Mitloehner, UC Davis animal science professor and air quality specialist in Cooperative Extension, and director of the UC Davis CLEAR Center. “California dairy farmers have demonstrated tremendous progress toward the state's methane reduction goal over the past several years. Given the short-lived nature of methane, this rapid reduction is an important contribution to the global effort to quickly limit climate warming.”
The author's analysis was prepared by Gladstein Neandross & Associates (GNA). Funding was provided by CDRF as part of its work to support an innovative and sustainable California dairy industry.
