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Jennifer W. MacAdam

Jennifer W. MacAdam

Professor - Plant Physiology and Forage Production
Area of Study: Crop Science, Plant Science, Agronomy
Employee Type: Faculty
Location:  AGRS 327
Office Phone:  435-797-2364
Fax:  435-797-3376
Cell Phone:  435-770-8019
Mailing Address:
Dept. of Plants, Soils & Climate
4820 Old Main Hill,
Logan Utah 84322-4820

Specialties: Forage production and physiology

Dr. MacAdam came to Utah State University in 1991, where her current appointment is 70% research, 20% teaching and 10% service.  Her research interests are (1) the management of seeded, irrigated pastures for grazing-based livestock production, (2) plant responses to salinity and drought stress, and (3) the development and regulation of leaf growth in grasses.

Dr. MacAdam teaches an introductory course in plant physiology and plant anatomy that emphasizes hands-on laboratory experiences and employs plants of value to agronomy and horticulture.  She has authored a text for the course, Structure & Function of Plants, that was published by Wiley-Blackwell in 2009.

Dr. MacAdam is an active member of the American Society of Agronomy and the Crop Science Society of America, serving in 2003 as chair of CSSA Division C-6 (Forage and Grazinglands) and as a technical editor of Forage and Grazinglands and an associate editor of Crop Science and Agronomy Journal.

Research Expertise and Relevance

Dr. MacAdam’s expertise is in the anatomy and physiology of forage crop plants, and her work is focused on issues of importance to livestock producers, particularly those grazing irrigated forages. She has studied leaf growth and development in tall fescue, the effect of frost and growth at suboptimal temperatures on the potential for bloat in alfalfa, and the management and productivity of irrigated forage grasses and legumes under rotational stocking management.

Upon determining that birdsfoot trefoil, a valuable tannin-containing legume, was uniquely well-adapted to the cool, dry climate and high pH soils of the northern Mountain West, her work has turned to the use of birdsfoot trefoil grazing to increase the rate of milk and meat production on irrigated pastures, and determination of the quality and acceptability of meat and milk from pastured animals relative to conventionally produced meat and milk. Her work has found increased production, elevated omega-3 fatty acids, and reduced enteric (digestive) methane production.

Follow this link to the publication Raising the Steaks, a report issued in February of 2011 by the Union of Concerned Scientists on the best approaches for mitigating greenhouse gas production by moving U.S. beef production from feedlots to pastures.  The text box on page 16 references a 2006 review article on birdsfoot trefoil in Forage and Grazinglands authored by Dr. MacAdam and others.

My Research: Irrigated Legumes for Livestock Production in the Intermountain West

My Class: PSC 3500 - The Structure and Function of Economic Crop Plants

My Textbook: Structure and Function of Plants

Earned Degrees




University of Missouri - Columbia




University of Missouri - Columbia




Missouri State University

Professional Employment

Utah State University, Dept. of Plants, Soils, and Climate
         Associate Professor, 1997-present
         Assistant Professor, 1991-1997
University of Missouri - Columbia, Dept. of Agronomy
         Postdoctoral Fellow, Interdisciplinary Plant Group, 1989-1991
         Instructor, Spring Semester, Crop Physiology Course, 1990
University of Missouri - Columbia, Dept. of Animal Sciences
         Postdoctoral Fellow, Ruminant Nutrition Group, 1988-1989
University of Missouri - Columbia, Dept. of Agronomy
         Graduate Research Assistant, Forage Physiology, 1982-1988

Courses Taught

PLSC 3500 Structure & Function of Plants
         3 semester credit junior-level lecture and laboratory course
         1998 to present
PLSC 4320, Forage Production and Pasture Ecology
         4 quarter credit / 3 semester credit senior-level lecture and laboratory course
         1991 to 2001
PLSC 6430, Plant Nutrition (co-instructed with Bruce Bugbee)
         3 quarter credit / 2 credit semester graduate lecture course, taught alternate years
         1993 to 1997

Publications Accepted or in Press (*corresponding author)

Christensen, R.G., S.-Y. Yang*, J.-S. Eun, B. Min and J.W. MacAdam. In vitro effects of birdsfoot trefoil (Lotus corniculatus L.) pasture on ruminal fermentation, microbial population, and methane production. Canadian Journal of Animal Science. Accepted with minor revisions, 1 September 2015.

Recent Publications

Hunt. S.R., J.W. MacAdam*, and T.C. Griggs. 2016. Seeding rate, oat companion crop and planting season effects on irrigated organic birdsfoot trefoil stands in the Mountain West USA. Crop Science 56: 4
Villalba*, J.J., C. Spackman, B.M. Goff, J.L. Klotz, T.C. Griggs, and J.W. MacAdam. 2016. Interaction between a tannin-containing legume and endophyte-infacted tall fescue seed on lambs' feeding behavior and physiology. Journal of Animal Science.
Christensen, R.G., S.-Y. Yang*, J.-S. Eun, A. Young, J. Hall and J.W. MacAdam. 2015. Effects of feeding birdsfoot trefoil hay on neutral detergent fiber digestion, nitrogen utilization efficiency, and lactational performance by dairy cows. Journal of Dairy Science 98: 7982-7992.
Grabber*, J.H., W.K. Coblentz, H. Riday, T.C. Griggs, D.H. Min, J.W. MacAdam and K.A. Cassida. 2015. Protein and dry matter degradability of European- and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental USA. Crop Science 55: 1356-1364.
Hunt, S.R., J.W. MacAdam* and J.R. Reeve. 2015. Establishment of birdsfoot trefoil (Lotus corniculatus) pastures on organic dairy farms in the Mountain West USA. Organic Agriculture 5:63-77.
MacAdam*, J.W. and J.J. Villalba. 2015. Beneficial effects of temperate forage legumes that contain condensed tannins. Agricultue 5:475-491.
Grabber*, J. H. Riday, K. Cassida, T. Griggs, D.-H. Min and J.W. MacAdam. 2014. Yield, morphological characteristics, and chemical composition of European and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental USA. Crop Science 54: 1893-1901.
Hunt, S.R., T.C. Griggs and J.W. MacAdam*. 2014. Change in birdsfoot trefoil (Lotus corniculatus) nutritive value with stem elongation, flowering and pod formation. In A. Hopkins et al. (ed) Proceedings of the European Grassland Federation, Aberystwyth, Wales, 7-11 September 2014. Grassland Science in Europe 19: 884-886.
Hunt, S.R., J.W. MacAdam* and T.C. Griggs. 2014. Lignification and tannin localization during the development of birdsfoot trefoil stems. Crop Science 54: 1876-1886.
Curtis*, K., T. Knudsen, and J. MacAdam. 2013. Northern Utah small cow-calf pasture finished beef production costs & returns, 2012. Electronic Bulletin AG/ Applied Economics /2013-01pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=15321&custom=1
Curtis*, K., MacAdam, J. and T. Knudsen. 2013. Annual costs to establish and maintain birdsfoot trefoil pastures in northern Utah, 2012. Electronic Bulletin AG/ Agribusiness/2013-01pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=15320&custom=1
Hafla, A.N., J.W. MacAdam* and K.J. Soder. 2013. Sustainability of US Organic Beef and Dairy Production Systems: Soil, Plant and Cattle Interactions. Sustainability 5: 3009-3034.
MacAdam*, J.W., J. Brummer, A. Islam, and G. Shewmaker. 2013. The benefits of tannin-containing forages. Electronic Bulletin. AG/Forages/2013?03pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=15457&custom=1
MacAdam*, J.W. and T.C. Griggs. 2013a. Irrigated birdsfoot trefoil variety trial: Forage yields. Electronic Bulletin AG/Forages/2013?01pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=15330&custom=1
MacAdam*, J.W. and T.C. Griggs. 2013b. Irrigated birdsfoot trefoil variety trial: Forage nutritive value. Electronic Bulletin. AG/Forages/2013?02pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=15329&custom=1
MacAdam*, J.W., S.R. Hunt, S. Martini, R.G. Christensen and J.-S. Eun. 2013. Meat and milk production on irrigated birdsfoot trefoil pastures in the Mountain West USA. P. Nichols et al. (Ed.) Proceedings of the XXII International Grassland Congress, 15-19 September 2013, Sydney, Australia.
MacAdam*, J.W., S. Martini and T.C. Griggs. 2013. The potential for reducing the carbon dioxide equivalent of beef production by finishing cattle on pure Lotus corniculatus pastures compared with grain-based feedlot finishing. R. Dewhurst et al. (Ed.) Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference, 23-26 June 2013, Dublin, Ireland. Advances in Animal Biosciences 4 (Part 2) 323.
Tracy* B., K. Albrecht, J. Flores, M. Hall, A. Islam, G. Jones, W. Lamp, J. MacAdam, H. Skinner, and C. Teutsch. 2013. Forage yield, weed suppression and fertilizer nitrogen replacement value (FNRV) of alfalfa-tall fescue mixtures. Grassland Science in Europe. 18:192-194.
Barker*, D., T. Butler, J.W. MacAdam and R.M. Sulc. 2012. Forage and biomass planting, pp. 41-110 In C.J. Nelson (ed.) Conservation Outcomes from Pastureland and Hayland Practices: Assessment, Recommendations, and Knowledge Gaps. Allen Press, Lawrence, Kansas.
Curtis*, K., Z. Ma, J. MacAdam, and V. Chakreeyarat. 2012. Rancher adoption potential of the birdsfoot trefoil pasture beef production system in the Intermountain West. Electronic Bulletin AG/Agribusiness/2012-03pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=14973&custom=1
MacAdam*, J. and R. Brain. 2012. Beef production & consumption: Sustainable alternatives. Electronic Bulletin Sustainability/2012/04pr. Utah State University Cooperative Extension Service, Logan. http://extension.usu.edu/htm/publications/publication=14852&custom=1
Ballif, J, S. Endo, M. Kotani, J. MacAdam, and Y. Wu*. 2011. Over-expression of HPA3b enhances primary root elongation in Aribidopsis. Plant Physiology and Biochemistry 49: 579-583.
MacAdam*, J.W., R.E. Ward, T.C. Griggs, B.R. Min, and G.E. Aiken. 2011. Average daily gain and blood fatty acid composition of cattle grazing the non-bloating legumes birdsfoot trefoil and cicer milkvetch in the Mountain West. Professional Animal Scientist 27:574-583.
Williams, C. M., J.-S. Eun*, J. W. MacAdam, A. Young, V. Fellner, and B.-R. Min. 2011. Effects of forage legumes containing condensed tannins on methane and ammonia production in continuous cultures of mixed ruminal microorganisms. Animal Feed Science Technology 166-167: 364-372
Williams, C. M., J.-S. Eun*, C. M. Dschaak, J. W. MacAdam, B.-R. Min, and A. Young. 2010. In vitro ruminal fermentation characteristics of birdsfoot trefoil (Lotus corniculatus L.) hay in continuous cultures. Professional Animal Scientist 26: 570–576.
Williams, C. M., J.-S. Eun*, J. W. MacAdam, A. Young, V. Fellner, and B.-R. Min. 2010. Tannin-free and tanniniferous legumes in lactating dairy diets affect in vitro ruminal fermentation characteristics and methane production by mixed ruminal microbiota in continuous cultures, pp. 159. In E. J. McGeough and S. M. McGinn (ed) Proceedings of the 4th International Conference on Greenhouse Gases and Animal Agriculture, Banff, Canada, October 3-8 2010. Agri-Food Canada, Lethbridge, Alberta, Canada.