Effective feeding strategies to reduce the carbon footprint of dairy cattle

Farm practices aiming at reducing the carbon footprint should be based on sound understanding of the methods available to reduce methane emissions from cattle. Dr. Ermias Kebreab is Associate Dean and Professor of Animal Science at the University of California, Davis. He is one of the worlds’ leading experts in animal nutrition, mathematical modeling of biological systems and impact of livestock on the environment. During a webinar entitled “Effective strategies to reduce the carbon footprint of dairy cattle” (May 26, 2023), he discussed ways to reduce carbon footprint that can be employed by the livestock industry to reach net zero livestock production by 2050. He also discussed what potential impact the different stakeholders within the industry can have on methane from cows and the dairy carbon footprint.

There are 2 planet boundaries (phosphorus and biodiversity) for which we are beyond the zone of uncertainty. For greenhouse gas emissions we are still within the zone of uncertainty, which means that we are at risk and we need to find ways to reduce the carbon footprint of dairy farming. Out of the greenhouse gasses, methane of cows is the most relevant target. In the US, 35% of total methane emissions is coming from livestock (see figure 1), with beef making the biggest contribution to the carbon footprint of livestock.

To achieve the goals set by the Global Methane Pledge, signed by over 150 countries, we need feeding strategies and other ways to reduce the carbon footprint of dairy farming. Methane mitigation strategies for reducing the carbon footprint of cattle should target enteric methane from cows as well as methane coming from manure. Greenhouse gas emissions from cattle went down by 45% between 1974 and 2014. The target for the future is reducing the carbon footprint of dairy farming by 50% by 2030, after which we should reduce methane emission from cattle by 1% per year.

There are several trade industry commitments. The US dairy industry for example has collectively committed to environmental stewardship goals, including goals for reducing the carbon footprint. The following targets are to be reached by 2050:

• Greenhouse gas neutrality
• Optimimum use of water while maximizing recycling
• Improved water quality by optimizing utilization of manure and nutrients

Various stakeholders have set targets for reducing the carbon footprint of their operations (see figure 2). A typical target that milk processors set for dairy producers for reducing carbon footprint is a reduction of methane from cows by 20-25%.

Firstly, an effective methane mitigation strategy could be to reduce consumption of animal proteins. Next to that, there are product related strategies for reduction of methane from cows. Genetic selection and feeding strategies are effective ways to reduce the carbon footprint per kg of ECM or per kg of meat produced. Dr Kebreab discussed a number of product related ways to reduce carbon footprint of cattle:

• Feeding strategies to improve feed efficiency (reducing the carbon footprint by 0.47 to 0.8% per year)
• Genetic selection (reducing the carbon footprint by 11-26% by 2030)
• Manure management
  • Anaerobic digester (to reduce methane emission from cattle by 15 to 25% per year)
  • Covered storage (to reduce methane emission from cattle by 15 to 25% per year)

There are several classes of feed additives for ruminants with a direct effect on rumen fermentation, leading to a reduction of cow methane production in the rumen. Some of these feed additives aimed at methane mitigation could be combined. For Selko IntelliBond it has been shown that it can be used for reducing the carbon footprint of cattle by 2%. 3NOP has a proven reduction of 12% of the dairy carbon footprint. As both products have a different mode of action to reduce enteric methane from cows, combined use is a method for reducing the carbon footprint by 14%. For the future, using microbial genomics of rumen flora might be one of the new ways to reduce the carbon footprint of dairy farming. The use of feed additives for reducing the carbon footprint can reduce methane emissions from cattle by 2 to >12% per year.

Dr. Kebreab concluded that the cattle industry has made tremendous achievements in reducing the carbon footprint of cattle farming during the last 50 years. Several stakeholders have made firm commitments for reducing the carbon footprint of cattle farming, to reach climate neutrality by 2050.