Olivia F. Godber¹, Karl J. Czymmek², Michael E. van Amburgh³ and Quirine M. Ketterings¹
¹Nutrient Management Spear Program, ²PRO-DAIRY, and ³Dairy Nutrition, Department of Animal Science, Cornell University, Ithaca, NY 14853
Introduction
In a recent study, 36 medium to large dairy farms (>300 cows) located across New York state were assessed for greenhouse gas (GHG) emissions for the 2022 calendar year using The Cool Farm Tool. Cows were predominantly Holstein. Dairies ranged in animal density from 0.71 to 1.96 animal units per acre (one animal unit is 1000 pounds of live weight). Herds produced an average fat and protein corrected milk (FPCM) yield of 29 000 lbs per cow per year using 64% homegrown feed. Total FPCM production was 1.92 billion lbs, sold to four dairy cooperatives. This milk production represented approximately 12% of total NY milk production in 2022.
Findings
The GHG emission intensity ranged from 0.63 to 1.06 lb CO₂eq per lb of FPCM (mean GHG emission intensity = 0.86 lb CO₂eq per lb FPCM). Methane was the biggest contributor, accounting for 60% of total GHG emissions on average, with enteric methane as the largest contributor (45% of total farm emissions). With several studies suggesting the US average GHG intensity of around 1lb CO₂eq per lb FPCM, this study shows these New York dairies to be leaders in sustainability.
The relatively low GHG emission intensity achieved by the farms in this study reflect high quality and quantity of home-grown feed, careful nutrient management, quality nutrition and high animal productivity, and for several of the farms also the installation of more advanced manure management systems such as solid-liquid separation with cover and flare, and anerobic digesters. These characteristics allow optimization of milk production through high feed efficiency, demonstrate the recognition of the value of manure offsetting synthetic fertilizer use, and the farm’s ability to take advantage of the dilution of maintenance concept through high milk yields and components.
Another important finding of the study is that many of the key drivers of GHG emission intensity for these farms were related to homegrown feed production and manure management, two main areas of management that also impact whole farm nutrient use efficiency. Reducing fertilizer and feed purchases not only benefits the GHG emission intensity of the farm but also contribute to improvements in whole farm nitrogen and phosphorus balances and improves farm economics.
Highlights
• Medium to large New York dairy farms in a recent study averaged a GHG intensity of 0.86 lb CO₂eq per lb of fat and protein corrected milk, much lower than the national average.
• Manure management system (implementation of solid-liquid separation with cover and flare, and anaerobic digesters), was a major driver of lower GHG emissions on the farms.
• Homegrown feed (both total amount and quality), heifer/cow ratio, and feed efficiency all impacted emissions with reduced emissions for integrated farms that grow a large portion of the forages fed to the cows on the farm itself, have lower heifer/cow ratios, and for farms that implemented precision feed management.
Invitation
The farms in this study represent a considerable proportion of New York’s milk production but expansion of the database will be needed to develop additional understanding of drivers of emissions and opportunities for improvements over time. Many of the farms that participated with 2022 data are continuing to participate now with 2023 and 2024 data. We welcome additional farms to join and would particularly also invite more farms with under 300 cows to participate to better represent the diverse New York dairy industry.
Full Citation
This article is summarized from our peer-reviewed publication: Godber, O.F., K.J. Czymmek, M.E. van Amburgh, and Q.M. Ketterings (2025). Farm-gate greenhouse gas emission intensity for medium to large New York dairy farms. Journal of Dairy Science. https://www.journalofdairyscience.org/article/S0022-0302(25)00124-9/fulltext.
Acknowledgments
We thank the farmers and farm advisors and coops that participated in the assessment. For questions about these results or inquiries about participating, contact Quirine M. Ketterings at 607-255-3061 or qmk2@cornell.edu, and/or visit the Cornell Nutrient Management Spear Program website at: http://nmsp.cals.cornell.edu/.
