Thomas Overton

Department Chair, Professor of Dairy Nutrition and Management, Animal Science

Program Director, PRO-DAIRY

About
Research Focus
Outreach and Extension Focus
Teaching Focus

The objective of my total program is to enhance the productive efficiency and profitability of dairy farm businesses in New York and beyond. My major emphasis is on dairy cattle well-being during the transition period from late pregnancy to early lactation because it is the most critical period of the lactation cycle.

The goals of my research program are to further our understanding of physiology and to develop nutritional and management strategies for dairy producers to use to improve animal well-being and in turn profitability. This research provides the foundation for my extension program, which topically is oriented toward nutrition and management of transition cows along with other aspects of dairy management. My extension program delivers this knowledge to agriservice professionals, dairy farm owners, and dairy farm employees.

Presentations and Activities

Overton, T. R. Turbocharge your fresh cows. Proceedings, California ARPAS Annual Meeting, Coalinga, CA. 2024.
Overton. T. R. Using high oleic soybeans in dairy diets. Proceedings, Cornell Nutrition Conference for Feed Manufacturers. Syracuse, NY. 2024.
Overton, T. R. Key opportunities to manage metabolism in transition dairy cows. Proceedings, DSM Global Conference, Cancun, MX. 2023.
Overton, T. R. Feeding transition cows – what is new and what do we still need to learn? Proceedings, Professional Dairy Producers of Wisconsin Dairy Business Conference, Wisconsin Dells, WI. 2022.
Overton, T. R. Updates on the transition cow period – Nutritional and management recommendations. Proceedings, Professional Dairy Producers of Wisconsin Dairy Business Conference, Wisconsin Dells, WI. 2022.
Westhoff, T. A., T. R. Overton, M. E. Van Amburgh, J. N. Tikofsky, and S. Mann. Pre- and postpartum metabolizable protein supply alters performance of multiparous Holstein cows. Proceedings, Cornell Nutrition Conference for Feed Manufacturers. Syracuse, NY. 2023.
Graef, G. M., A. L. Kerwin,.L. N. Ferro, S. Ordaz-Puga, C. M. Ryan, T. A. Westhoff, D. M. Barbano, K. M. Glosson, K. P. Zanzalari, J. D. Chapman, and T. R. Overton. Effect of prepartum DCAD strategy and level of dietary calcium on postpartum calcium status and performance of multiparous Holstein cows. Proceedings, Cornell Nutrition Conference for Feed Manufacture. 2021.
Westhoff, T. A., T. R. Overton, and S. Mann. Epidemiology of bovine colostrum production in New York Holstein herds: Cow, management, nutritional, and environmental factors. Proceedings, Cornell Nutrition Conference for Feed Manufacturers. Syracuse, NY. 2022.
Graef, G. M., A. L. Kerwin,.L. N. Ferro, S. Ordaz-Puga, C. M. Ryan, T. A. Westhoff, D. M. Barbano, K. M. Glosson, K. P. Zanzalari, J. D. Chapman, and T. R. Overton. Effect of prepartum DCAD strategy and level of dietary calcium on postpartum calcium status and performance of multiparous Holstein cows. Proceedings, Cornell Nutrition Conference for Feed Manufacturers. Syracuse, NY. 2021.
Kerwin, A. L., W. S. Burhans, D. V. Nydam, and T. R. Overrton. Relationships between transition cow nutrition and management strategies and outcomes in large dairy herds in the Northeastern US. Proceedings, Cornell Nutrition Conference for Feed Manufacturers. Syracuse, NY. 2021.

Education

Doctorate
University of Illinois, 1998
Master of Science
University of Illinois, 1994
Bachelor of Science
Cornell University, 1991

Recent Research

Westhoff, T. A., T. R. Overton, J. N. Tikofsky, M. E. Van Amburgh, C. M. Ryan, and S. Mann. 2024. Pre- and postpartum metabolizable protein supply: I. Effects on feed intake, lactation performance, and metabolic markers in transition dairy cows. J. Dairy Sci. 107:10882-10899. doi: 10.3168/jds.2024-25026.
Kerwin, A. L., W. S. Burhans, D. V. Nydam, and T. R. Overton. 2023. Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part III – Associations of management and dietary factors with analytes, health, milk yield, and reproduction. J. Dairy Sci. 106:1246-1266. doi: 10.3168/jds.2022-21876
Kerwin, A. L, W. S. Burhans, D. V. Nydam, and T. R. Overton. 2023. Transition cow nutrition and management strategies of dairy herds in the Northeastern United States: Association of nutritional strategies with analytes, health, milk yield, and reproduction. Animals (Basel). 13:2701. doi: 10.3390/ani13172701
Kerwin, A. L., G. M. Graef, C. M. Ryan, L. Ferro, S. Ordaz Puga, T. A. Westhoff, D. M. Barbano, D. H. Kleinschmit, and T. R. Overton. 2023. Effect of replacing a portion of inorganic chloride trace minerals with trace mineral amino acid complexes. J. Dairy Sci. 106:6128-6145. doi: 10.3168/jds.2022-22953
Westhoff, T. A., T. R. Overton, and S. Mann. 2023. Epidemiology of bovine colostrum production in New York Holstein herds: Prepartum nutrition and metabolic indicators. J. Dairy Sci. 106:4896-4905. doi: 10.3168/jds.2022-22960
Kerwin A. L., W. S. Burhans, S. Mann, D. V. Nydam, S. K. Wall, K. M. Schoenberg, K. L. Perfield, and T. R. Overton. 2022. Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part II-Associations of metabolic- and inflammation-related analytes with health, milk yield, and reproduction. J. Dairy Sci. 105:5349-5369. doi: 10.3168/jds.2021-20863.
Kerwin A.L., W. S. Burhans, S. Mann, M. Tetreault, D. V. Nydam, and T. R. Overton. 2022. Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part I-Herd description and performance characteristics. J. Dairy Sci. 105:5327-5348. doi: 10.3168/jds.2021-20862.
Kerwin A. L., M. M. McCarthy, W. S. Burhans, D. V. Nydam, S. K. Wall, K. M. Schoenberg, K. L. Perfield, and T. R. Overton. 2022. Associations of a liver health index with health, milk yield, and reproductive performance in dairy herds in the northeastern United States. JDS Commun. 3:446-450. doi: 10.3168/jdsc.2022-0261
Seely, C. R., B. M. Leno, A. L. Kerwin, T. R. Overton, and J.A.A. McArt. 2021. Association of subclinical hypocalcemia dynamics with dry matter intake, milk yield, and blood minerals during the periparturient period. J. Dairy Sci. 104: 4692-4702.
Kerwin, A. L., C. M. Ryan, B. M. Leno, M. Jakobsen, P. Theilgaard, D. M. Barbano, and T. R. Overton. 2019. Effects of feeding synthetic zeolite A during the prepartum period on serum mineral concentration, oxidant status, and performance of multiparous Holstein cows. J. Dairy Sci. 102:5191-5207.
Overton, T. R., J.A.A. McArt, and D. V. Nydam. 2017. A 100-Year Review: Metabolic health indicators and management of dairy cattle. J. Dairy Sci. 100:10398-10417.

Awards & Honors

2024 Nutrition Professionals Applied Dairy Research Award - American Dairy Science Association
2010 CALS Award for Outstanding Accomplishments in Extension/Outreach – Team Award (PRO-DAIRY; with D. M. Galton, K, J. Czymmek, C. A. Gooch, K. F. Barrett, D. J. Grusenmeyer, J. Karszes, K. S. Skellie, T. A. Shepherd)
2007 Foundation Scholar Award and Lectur - American Dairy Science Association
2007 CALS Award for Outstanding Accomplishments in Extension/Outreach - Team Award (with L. E. Chase, D. G. Fox, and M. E. Van Amburgh)

Courses Taught

ANSC 1101: Contemporary Perspectives in Animal Science

ANSC 1105: Careers in Animal Science

ANSC 3550/5550: Dairy Cattle Nutrition

VETMED 6559: Applied Dairy Nutrition for Practitioners

Current Areas of Research Activity

My current area of research is nutritional management of the transition dairy cow. This phase of the lactation cycle continues to be the most important related to health and productivity. Research projects span from controlled research studies conducted at the Cornell University Ruminant Center Dairy as well as observational studies conducted in collaboration with commercial dairy farms in New York. Specific areas of work include:

Nutritional management of hypocalcemia as a gateway issue in transition cows
- Opportunities to improve performance through protein supplementation peripartum
- Inflammation in postpartum dairy cows
- Identification and validation of new biomarkers of metabolic and immune health in transition cows

My research provides the foundation for my extension program, which topically is oriented toward nutrition and management of transition cows along with other aspects of dairy management. My extension program delivers this knowledge to agriservice professionals, dairy farm owners and dairy farm employees.

In addition, I provide primary leadership to annual short courses in dairy nutrition and management for agriservice professionals and to major outreach efforts focused toward dairy farm owners and employees in conjunction with our PRO-DAIRY program. As Director of PRO-DAIRY, I provide leadership to statewide efforts to positively impact the dairy industry in New York.

Contact Information

272 Frank Morrison Hall
507 Tower Road
Ithaca, NY 14853

(607) 255-2878

tro2 [at] cornell.edu

- PRO-DAIRY
- Animal Science

Thomas in the news

News

March 4, 2026

Cornell CALS undergraduates awarded Richard Popp scholarships

Cornell CALS undergraduates Danielle Herrick, Lainey Koval, Lucas Walley and Sophia Woodis received the Richard Popp Scholarship award.

PRO-DAIRY
Animal Science
Dairy

Julio Giordano, professor of animal science in the College of Agriculture and Life Sciences, shows dairy industry leaders a collar that can track cows' food intake, at the Cornell University Ruminant Center on June 30.

News

July 3, 2025

‘Farm of the Future’ showcased at Cornell PRO-DAIRY celebration

On June 30, dairy industry leaders from New York state toured the Cornell University Ruminant Center, a one-of-a-kind testbed for new technologies and strategies and a crucial resource for the state's dairy farmers.

PRO-DAIRY
Animal Science
Animals