Professor
Education:
Ph.D. – University of Illinois - 1987
Discipline(s):
Environmental Quality
MAPLE
Nutrition
Microbiology
Websites of interest:
OSU Interdisciplinary PhD Program in Nutrition (OSUN)
Maple Team
Courses Taught:
Ruminant Nutrition (AS 630.01 – co-instructor)
Ruminant Physiology, Nutrition, and Metabolism (AS 730 – co-instructor)
Advanced Nutrient Utilization. Carbohydrate and Lipid Metabolism (AS/HN/FST 761 - co-instructor)
Grants & Awards:
OARDC Junior Faculty Research Award (1999)
Section Editor for the Journal of Animal Science (1999-2001, 2003-2005)
USDA NRI Competitive grant (2002-2007). Protozoal Ecology and Its Impact on Nitrogen Transactions in Ruminants
USDA NRI Competitive grant (2008-2011). Mechanisms coordinating protozoal growth and recycling toward improved efficiency of protein usage in the rumen.
American Dairy Science Association Nutrition Professionals Applied Dairy Nutrition Award (2003)
Director of the interdepartmental OSU Nutrition program in 2002 (http://www.hec.ohio-state.edu/osun/)
Gamma Sigma Delta Research Award of Merit (2006)
Publications:
Peer Reviewed Journal Articles (74 total)
Wolf, B.W., T.M.S. Wolever, C.S. Lai, C. Bolognesi, R. Radmard, K.S. Maharry, K.A. Garleb, S.R. Hertzler, and J.L. Firkins. 2003. Effects of a beverage containing an enzymatically induced-viscosity dietary fiber, with or without fructose, on the postprandial glycemic response to a high glycemic index food in humans. Eur. J. Clin. Nutr. 57:1120-1127.
Griswold, K.E., G.A. Apgar, J. Bouton, and J.L. Firkins. 2003. Effect of urea supplementation and ruminal degradable protein concentration on microbial growth, digestibility and fermentation in continuous culture. J. Anim. Sci. 81:329-336.
Karnati, S.K.R., Z. Yu, J.T. Sylvester, B.A. Dehority, M. Morrison, and J.L. Firkins. 2003. Technical Note: Specific PCR Amplification of Protozoal 18S rDNA Sequences from DNA Extracted from Rumen Samples of Cows. J. Anim. Sci. 81:812-815.
Noftsger, S.M., N.R. St-Pierre, S.K.R. Karnati, and J.L. Firkins. 2003. Effects of 2-Hydroxy-4-(methylthio) Butanoic Acid (HMB) on Microbial Growth in Continuous Culture. J. Dairy Sci. 86:2629-2636.
Qiu, X., M.L. Eastridge, J.L. Firkins, and K. Griswold. 2004. Effects of substrate, passage rate, and pH in continuous culture on flows of conjugated linoleic acid and trans C18:1. J. Dairy Sci. 87:3473-3479.
Sylvester, J.T., S.K.R. Karnati, Z. Yu, M. Morrison, and J.L. Firkins. 2004. Development of an assay to quantify rumen ciliate protozoal biomass in cows using real-time PCR. J. Nutr. 134:3378-3384.
Qiu, X., M.L. Eastridge, and J.L. Firkins. 2004. Effects of dry matter intake, addition of buffer, and source of fat on duodenal flow and concentration of conjugated linoleic acid and trans-11 C18:1 in milk. J. Dairy Sci. 87:4278-4286.
Sylvester, J.T., S.K.R. Karnati, Z. Yu, C.J. Newbold, and J.L. Firkins. 2005. Evaluation of a real-time PCR assay quantifying the ruminal pool size and duodenal flow of protozoal nitrogen. J. Dairy Sci. 88:2083-2095.
Reveneau, C., C.V.D.M. Ribeiro, M.L. Eastridge, N.R. St-Pierre, and J.L. Firkins. 2005. Processing whole cottonseed moderates fatty acid metabolism and improves performance by dairy cows. J. Dairy Sci. 88:4342-4355.
Karnati, S.K.R., J.T. Sylvester, S.M. Noftsger, Z. Yu, N.R. St-Pierre, and J.L. Firkins. 2007. Assessment of ruminal bacterial populations and protozoal generation time in cows fed different methionine sources. J. Dairy Sci. 90:798-809.
Ribeiro, C.V.D.M., M.L. Eastridge, J.L. Firkins, N.R. St-Pierre, and D.L. Palmquist. 2007. Kinetics of fatty acid biohydrogenation in vitro. J. Dairy Sci. 90:1405-1416.
Bhatti, S.A., J.G. Bowman, J.L. Firkins, A.V. Grove, and C.W. Hunt. 2008. Effect of intake level and alfalfa substitution for grass hay on ruminal kinetics of fiber digestion and particle passage in beef cattle. J. Anim. Sci. 86:134-145.
Firkins, J.L., B.S. Oldick, J. Pantoja, C. Reveneau, L.E. Gilligan, and L. Carver. 2008. Efficacy of liquid feeds varying in concentration and composition of fat, non-protein nitrogen, and non-fiber carbohydrates for lactating dairy cows. J. Dairy Sci. 91:1969-1984.
Sylvester, S.K.R. Karnati, B.A. Dehority, M. Morrison, G.L. Smith, N.R. St-Pierre, and J.L. Firkins. 2009.Rumen protozoa decrease generation time and adjust 18S rDNA copies to adapt to decreased transfer interval, starvation, and monensin. J. Dairy Sci. 92:256-269.
Oelker, E.R., C. Reveneau, and J.L. Firkins. 2009. Interaction of molasses and monensin in alfalfa hay- or corn silage-based diets on rumen fermentation, total tract digestibility and milk production by Holstein cows. J. Dairy Sci. 92:270-285.
Invited, Peer-Reviewed Journal Articles (8 total)
Firkins, J.L., A.N. Hristov, M.B. Hall, G.A. Varga, and N.R. St-Pierre. 2006. Integration of ruminal metabolism in dairy cattle. J. Dairy Sci. 89(E. Suppl.):E31-E51.
Firkins, J.L., Z. Yu, and M. Morrison. 2007. Ruminal nitrogen metabolism: Perspectives for integration of microbiology and nutrition for dairy. J. Dairy Sci. 90(E. Suppl.)E1-E16.
Firkins, J.L., S.K.R. Karnati, and Z. Yu. 2008. Linking rumen function to animal response by application of genomic function. Aust. J. Exp. Agr. 48:711-721.
Invited Book Chapters (4 total)
Eastridge, M.L., and J.L. Firkins. 2002. Cereal Grains. Roginski, H., J.W. Fuquay, and P.F. Fox, eds. Encyclopedia of Dairy Sciences. 1:478-483.
Firkins, J.L., and C.K. Reynolds. 2005. Whole animal nitrogen balance in cattle. A.N. Hristov and E. Peffer, eds. Nitrogen and Phosphorus Nutrition of Cattle and Environment pp 167-185.
Firkins, J.L. and Z. Yu. 2006. Characterisation and quantification of the microbial populations of the rumen. Pages 19-54 in Ruminant Physiology, Digestion, Metabolism and Impact of Nutrition on Gene Expression, Immunology and Stress. K. Sejrsen, T. Hvelplund, and M.O. Nielsen, eds. Wageningen Academic Publishers, Wageningen, The Netherlands.
Species:
Dairy
Dr. Firkins research activities are mainly prioritized in three different areas: 1) improving the efficiency of microbial protein synthesis to enhance the conversion of dietary protein into milk protein; 2) studying the interactions of physical, chemical, and microbiological processes related to fiber degradation and passage in the rumen to improve the efficiency of fiber and starch utilization in dairy cattle; and 3) improving the quantitative prediction of protein and carbohydrate digestion and metabolism in dairy cattle. He collaborates and leads research in other projects related to carbohydrate metabolism in human nutrition and the efficient usage of protein, fat, and carbohydrate sources in ruminant nutrition.
