Ermias Kebreab, Ph.D.

Ermias Kebreab

Position Title
Professor and Sesnon Endowed Chair
Associate Dean of Global Engagement, CA&ES
Director, World Food Center

2111 Meyer Hall


  • B.S., Biology, University of Asmara, Eritrea, 1987.
  • M.S., Integrative biology, University of Reading, UK, 1991.
  • Ph.D., Ecological modeling, University of Reading, UK, 1998.

Research Interests

My current research interests are:

  1. Whole system approach to quantifying greenhouse gas emissions in agriculture. Mathematical modeling and mitigation of emissions from animals, manure and soil.
  2. Development of energy and nutrient utilization/requirement models in cattle, swine and poultry
  3. Sustainable agriculture, in particular animal production in relation to environmental sustainability.

Graduate Groups

Courses Taught

  • Mathematical Modeling in Biological Systems (ABG250)
  • Sustainable Animal Agriculture (ANS 112)
  • Enterprise Analysis in Animal Industries (ANS 148)


For current and past lab member bios, please visit the Animal Nutrition & Environment Modeling Applications Laboratory (ANEMAL) website via the links below.

Selected Publications


Jayasundara, S., J. A. D. R. N. Appuhamy, E. Kebreab and C. Wagner-Riddle. 2016. Methane and nitrous oxide emissions from Canadian dairy farms and mitigation options: An updated review. Can. J. Anim. Sci., 96: 306–331.

Caro, D., Kebreab, E. and F. Mitloehner. 2016. Mitigation of enteric methane emissions from global livestock systems through nutrition strategies. Climatic Change, 137:467-480.

Yáñez-Ruiz D.R., A. Bannink, J. Dijkstra, E. Kebreab, D.P. Morgavi, P. O´Kiely, C. K. Reynolds, A. Schwarm, K.J. Shingfield, Z. Yu, and A.N. Hristov. 2016. Design, implementation and interpretation of in vitro batch culture experiments to assess enteric methane mitigation in ruminants – a review. Anim. Feed Sci. Technol., 216:1-18.

Santiago-Juarez, B., L.E. Moraes, J.A.D.R.N. Appuhamy, W.F. Pellikaan, D.P. Casper, J. Tricarico and E. Kebreab. 2016. Prediction and evaluation of enteric methane emissions from lactating dairy cows using different levels of covariate information. Anim. Prod. Sci. 56: 557-564.

Niu, M., J.A.D.R.N. Appuhamy, A. Leytem, R. Dungan and E. Kebreab. 2016. Effect of dietary crude protein and forage contents on enteric methane emissions and nitrogen excretion from dairy cows simultaneously. Anim. Prod. Sci. 56:312-321.

Bougouin A, Leytem A, Dijkstra J, Dungan RS, Kebreab E. Nutritional and Environmental Effects on Ammonia Emissions from Dairy Cattle Housing: A Meta-Analysis. J Environ Qual. 2016 Jul;45(4):1123-32.

Appuhamy JA, Judy JV, Kebreab E, Kononoff PJ. Prediction of drinking water intake by dairy cows. J Dairy Sci. 2016 Sep;99(9):7191-205.

Johnson AC, Reed KF, Kebreab E. Short communication: Evaluation of nitrogen excretion equations from cattle. J Dairy Sci. 2016 Sep;99(9):7669-78.

Kebreab E, Liedke A, Caro D, Deimling S, Binder M, Finkbeiner M. Environmental impact of using specialty feed ingredients in swine and poultry production: A life cycle assessment. J Anim Sci. 2016 Jun;94(6):2664-81.

Reed KF, Arhonditsis GB, France J, Kebreab E. Technical note: Bayesian calibration of dynamic ruminant nutrition models. J Dairy Sci. 2016 Aug;99(8):6362-70.

Appuhamy JA, France J, Kebreab E. Models for predicting enteric methane emissions from dairy cows in North America, Europe, and Australia and New Zealand. Glob Chang Biol. 2016 Sep;22(9):3039-56.

Martineau R, Ouellet DR, Kebreab E, Lapierre H. Casein infusion rate influences feed intake differently depending on metabolizable protein balance in dairy cows: A multilevel meta-analysis. J Dairy Sci. 2016 Apr;99(4):2748-61.

Lehmann JO, Fadel JG, Mogensen L, Kristensen T, Gaillard C, Kebreab E. Effect of calving interval and parity on milk yield per feeding day in Danish commercial dairy herds. J Dairy Sci. 2016 Jan;99(1):621-33.

Alvarez-Fuentes G, Appuhamy JA, Kebreab E. Prediction of phosphorus output in manure and milk by lactating dairy cows. J Dairy Sci. 2016 Jan;99(1):771-82.


Moraes LE, Fadel JG, Castillo AR, Casper DP, Tricarico JM, Kebreab E. Modeling the trade-off between diet costs and methane emissions: A goal programming approach. J Dairy Sci 2015 Aug;98(8):5557-71.

Moraes LE, Kebreab E, Strathe AB, Dijkstra J, France J, Casper DP, Fadel JG. Multivariate and univariate analysis of energy balance data from lactating dairy cows. J Dairy Sci 2015;98(6):4012-29.

Strathe AV, Strathe AB, Theil PK, Hansen CF, Kebreab E. Determination of protein and amino acid requirements of lactating sows using a population-based factorial approach. Animal 2015:1-10.

Reed KF, Moraes LE, Casper DP, Kebreab E. Predicting nitrogen excretion from cattle. J Dairy Sci 2015;98(5):3025-35.

Strathe AB, Danfaer A, Jorgensen H, Kebreab E. A dynamic growth model for prediction of nutrient partitioning and manure production in growing-finishing pigs: Model development and evaluation. J Anim Sci 2015;93(3):1061-73.

Vaz PG, Kebreab E, Hung SS, Fadel JG, Lee S, Fangue NA. Impact of nutrition and salinity changes on biological performances of green and white sturgeon. PLoS One 2015;10(4):e0122029.

Reed, K.F., D.P. Casper, J. France and E. Kebreab. 2015. Prediction of nitrogen efficiency in dairy cattle: a review. CAB Reviews, 10: No. 001, p. 1-12.

Lopez S, France J, Odongo NE, McBride RA, Kebreab E, AlZahal O, McBride BW, Dijkstra J. On the analysis of Canadian Holstein dairy cow lactation curves using standard growth functions. J Dairy Sci 2015;98(4):2701-12.

Arias, R. A., A. Catrileo, R. Larraín, R. Vera, A. Velásquez, M. Toneatti, J. France, J. Dijkstra and E. Kebreab. 2015. Estimating enteric methane emissions from Chilean beef fattening systems using a mechanistic model. J. Agric. Sci., 153:114–123.


Jordan, N., J. Grossman, P. Lawrence, A. Harmon, W. Dyer, B. Maxwell, K.V. Cadieux, R. Galt, A. Rojas, C. Byker, S. Ahmed, T. Bass, E. Kebreab, V. Singh, T. Michaels, and C. Tzenis. 2014. New Curricula for Undergraduate Food-Systems Education: A Sustainable Agriculture Education Perspective. NACTA Journal, 302-310.

Appuhamy JA, Kebreab E, Simon M, Yada R, Milligan LP, France J. Effects of diet and exercise interventions on diabetes risk factors in adults without diabetes: meta-analyses of controlled trials. Diabetol Metab Syndr 2014;6:127.

Ellis, J. L., J. Dijkstra, A. Bannink, E. Kebreab, S. Archibeque, C. Benchaar, K. A. Beauchemin, J. D. Nkrumah and J. France. 2014. Improving the prediction of methane production and representation of rumen fermentation for finishing beef cattle within a mechanistic model. Can. J. Anim. Sci. 94: 509-524.

Appuhamy, J.A.D.R.N., L.E. Moraes, C. Wagner-Riddle, D.P. Casper J. France, and E. Kebreab. 2014. Development of mathematical models to predict volume and nutrient composition of fresh manure from lactating Holstein cows. Animal Production Science, 54:1927-1938.

Moraes, L.E., E. Kebreab, A. B. Strathe, J. France, J. Dijkstra, D.P. Casper, and J.G. Fadel. 2014. Bayesian analysis of energy balance data from growing cattle using parametric and non-parametric modelling. Animal Production Science, 54:2068-2081.

Reed, K.F., L.E. Moraes, J.G. Fadel, D.P. Casper, J. Dijkstra, J. France and E. Kebreab. 2014. Prediction of nitrogen use in dairy cattle: a multivariate Bayesian approach. Animal Production Science, 54:1918-1926.

Appuhamy JA, Wagner-Riddle C, Casper DP, France J, Kebreab E. Quantifying body water kinetics and fecal and urinary water output from lactating Holstein dairy cows. J Dairy Sci 2014;97(10):6177-95.

Bougouin A, Appuhamy JA, Kebreab E, Dijkstra J, Kwakkel RP, France J. Effects of phytase supplementation on phosphorus retention in broilers and layers: a meta-analysis. Poult Sci 2014;93(8):1981-92.

Moraes LE, Strathe AB, Fadel JG, Casper DP, Kebreab E. Prediction of enteric methane emissions from cattle. Glob Chang Biol 2014;20(7):2140-8.

Hansen AV, Strathe AB, Theil PK, Kebreab E. Energy and nutrient deposition and excretion in the reproducing sow: model development and evaluation. J Anim Sci 2014;92(6):2458-72.

Rendón-Huerta, J.A., J. M. Pinos-Rodríguez, J. C. García-López, L. G. Yáñez-Estrada and E. Kebreab. 2014. Trends of greenhouse gas emissions by dairy cattle in México between 1970 and 2010. Anim. Prod. Sci. 54: 292-298.

Asgedom, H., M. Tenuta, D. N. Flaten, X. Gao, E. Kebreab. 2014. Nitrous oxide emissions from a clay soil receiving granular urea formulations and dairy manure. Agronomy J. 106:732-744.

Hristov AN, Johnson KA, Kebreab E. Livestock methane emissions in the United States. Proc Natl Acad Sci U S A 2014;111(14):E1320.

Kebreab, E. 2014. Framework of innovation for a sustainable future in animal agriculture - mini review. CAB Reviews 9(006):1-2.

Steenwerth, K. L., A. K. Hodson, A. J. Bloom, M. R. Carter, A. Cattaneo, C. J. Chartres, J. L. Hatfield, K. Henry, J. W. Hopmans, W. R. Horwath, B. M. Jenkins, E. Kebreab, R. Leemans, L. Lipper, M. N. Lubell, S. Msangi, R. Prabhu, M. P. Reynolds, S. S. Solis, W. M. Sischo, M. Springborn, P. Tittonell, S. M. Wheeler, S. J. Vermeulen, E. K. Wollenberg, and L. S. Jarvis. 2014. Climate-smart agriculture global research agenda: scientific basis for action. Agriculture and Food Security 3(11).


Hristov AN, Oh J, Firkins JL, Dijkstra J, Kebreab E, Waghorn G, Makkar HP, Adesogan AT, Yang W, Lee C, Gerber PJ, Henderson B, Tricarico JM. Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options. J Anim Sci 2013;91(11):5045-69.

Hristov AN, Ott T, Tricarico J, Rotz A, Waghorn G, Adesogan A, Dijkstra J, Montes F, Oh J, Kebreab E, Oosting SJ, Gerber PJ, Henderson B, Makkar HP, Firkins JL. Mitigation of methane and nitrous oxide emissions from animal operations: III. A review of animal management mitigation options. J Anim Sci 2013;91(11):5095-113.

Kebreab, E., A.V. Hansen and A.B. Leytem. 2013. Feed management practices to reduce manure phosphorus excretion in dairy cattle. Adv. Anim. Biosci. 4 s1:37-41.

von Keyserlingk MA, Martin NP, Kebreab E, Knowlton KF, Grant RJ, Stephenson M, Sniffen CJ, Harner JP, 3rd, Wright AD, Smith SI. Invited review: Sustainability of the US dairy industry. J Dairy Sci 2013;96(9):5405-25.

France J, Lopez S, Kebreab E, Dijkstra J. Interpreting experimental data on egg production--applications of dynamic differential equations. Poult Sci 2013;92(9):2498-508.

Appuhamy JA, Strathe AB, Jayasundara S, Wagner-Riddle C, Dijkstra J, France J, Kebreab E. Anti-methanogenic effects of monensin in dairy and beef cattle: a meta-analysis. J Dairy Sci 2013;96(8):5161-73.

Appuhamy JA, Kebreab E, France J. A mathematical model for determining age-specific diabetes incidence and prevalence using body mass index. Ann Epidemiol 2013;23(5):248-54.

Dias, R. S., S. López, R. M. Patiño, T. S. Silva, J. C. Silva Filho, D. M. S. S. Vitti, M. R. S. R. Peçanha, E. Kebreab and J. France. 2013. Calcium and phosphorus utilization in growing sheep supplemented with dicalcium phosphate. J. Agric Sci. 151:424-433.

Gerber PJ, Hristov AN, Henderson B, Makkar H, Oh J, Lee C, Meinen R, Montes F, Ott T, Firkins J, Rotz A, Dell C, Adesogan AT, Yang WZ, Tricarico JM, Kebreab E, Waghorn G, Dijkstra J, Oosting S. Technical options for the mitigation of direct methane and nitrous oxide emissions from livestock: a review. Animal 2013;7 Suppl 2:220-34.

Klop G, Ellis JL, Bannink A, Kebreab E, France J, Dijkstra J. Meta-analysis of factors that affect the utilization efficiency of phosphorus in lactating dairy cows. J Dairy Sci 2013;96(6):3936-49.


Kebreab E, Hansen AV, Strathe AB. Animal production for efficient phosphate utilization: from optimized feed to high efficiency livestock. Curr Opin Biotechnol 2012;23(6):872-7.

Strathe, A.B., H. Jørgensen, E. Kebreab and A. Danfær. 2012. Bayesian simultaneous equation models for the analysis of energy intake and partitioning in growing pigs. J. Agric. Sci. 150:764-774.

Ellis JL, Dijkstra J, Bannink A, Kebreab E, Hook SE, Archibeque S, France J. Quantifying the effect of monensin dose on the rumen volatile fatty acid profile in high-grain-fed beef cattle. J Anim Sci 2012;90(8):2717-26.

Darmani Kuhi, H., E. Kebreab and J. France. 2012. Application of law of diminishing returns to partitioning metabolizable energy and crude protein intake between maintenance and growth in egg type pullets. J. Appl. Poult. Res. 21:540-547.

Hansen AV, Strathe AB, Kebreab E, France J, Theil PK. Predicting milk yield and composition in lactating sows: a Bayesian approach. J Anim Sci 2012;90(7):2285-98.

Dumas, A., López, S., Kebreab, E., Gendron, M., Thornley, J.H.M. & France, J. (2012) Selection of growth functions for describing length-at-age relationships in fish species displaying different life history traits: unexpected alternatives to the von Bertalanffy equation and advantages of a pluralistic statistical approach. CAB Reviews 7, No 038:1-14.

Legesse, G., J. A. Small, S. L. Scott, E. Kebreab, G.H. Crow, H.C. Block, C.D. Robins, and W.P. McCaughey. 2012. Effects of alternative summer-pasture and winter-feeding systems for beef cows on cow/calf productivity. Can. J. Anim. Sci. 92: 89-102.

Ellis JL, Dijkstra J, France J, Parsons AJ, Edwards GR, Rasmussen S, Kebreab E, Bannink A. Effect of high-sugar grasses on methane emissions simulated using a dynamic model. J Dairy Sci 2012;95(1):272-85.

Dijkstra, J., J.L. Ellis, E. Kebreab, A.B. Strathe, S. Lopez, J. France and A. Bannink 2012. Ruminal pH regulation and nutritional consequences of low pH. Anim. Feed Sci. Tech. 172:22-33.


Dias RS, Lopez S, Patino RM, Silva TS, Silva Filho JC, Vitti DM, Pecanha MR, Kebreab E, France J. An extended model of phosphorus metabolism in growing ruminants. J Anim Sci 2011;89(12):4151-62.

Tomich, T.P., S. Brodt, H. Ferris, R. Galt, W. R. Horwath, E. Kebreab, J.H.J. Leveau, D. Liptzin, M. Lubell, P. Merel, R.W. Michelmore, T. Rosenstock, K. Scow, J. Six, N. Williams and L. Yang. 2011. Agroecology: A Review from a Global-Change Perspective. Ann. Rev. Environ. Resources 36:193-222.

Neijat M, House JD, Guenter W, Kebreab E. Calcium and phosphorus dynamics in commercial laying hens housed in conventional or enriched cage systems. Poult Sci 2011;90(10):2383-96.

Kebreab E, Strathe AB, Yitbarek A, Nyachoti CM, Dijkstra J, Lopez S, France J. Modeling the efficiency of phosphorus utilization in growing pigs. J Anim Sci 2011;89(9):2774-81.

Cooprider KL, Mitloehner FM, Famula TR, Kebreab E, Zhao Y, Van Eenennaam AL. Feedlot efficiency implications on greenhouse gas emissions and sustainability. J Anim Sci 2011;89(8):2643-56.

Modaresi J, Fathi Nasri MH, Rashidi L, Dayani O, Kebreab E. Short communication: effects of supplementation with pomegranate seed pulp on concentrations of conjugated linoleic acid and punicic acid in goat milk. J Dairy Sci 2011;94(8):4075-80.

Asgedom, H. and E. Kebreab. 2011. Beneficial management practices and mitigation of greenhouse gas emissions in the Canadian Prairie agriculture: a review. Agronomy Sust. Developm. 31:433–451.

Alemu, A.W., K. Ominski and E. Kebreab. 2011. Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models. Can. J. Anim. Sci., 91:305-321.

Strathe, A.B. A. Lemme, J.K. Htoo and E. Kebreab. 2011. Estimating digestible methionine requirements for laying hens using multivariate nonlinear mixed effect models. Poult. Sci., 90:1496-1507.

Legesse, G., J. A. Small, S. L. Scott, G. H. Crow, H. C. Block, A. W. Alemu, C. D. Robins and E. Kebreab. 2011. Predictions of enteric methane emissions for various summer pasture and winter feeding strategies for cow calf production. Anim. Feed Sci. Tech. 166-167:678-687.

Alemu, A.W., J. Dijkstra, A. Bannink, J. France and E. Kebreab. 2011. Rumen stoichiometric models and their contribution and challenges in predicting enteric methane production. Anim. Feed Sci. Tech. 166-167:761-778.

Darmani Kuhi, H., F. Rezaee, A. Faridi, J. France, M. Mottaghitalab and E. Kebreab. 2011. Application of the law of diminishing returns for partitioning metabolizable energy and crude protein intake between maintenance and growth in growing male and female broiler breeder pullets. J. Agric. Sci. 149, 385–394.

Ellis JL, Dijkstra J, Bannink A, Parsons AJ, Rasmussen S, Edwards GR, Kebreab E, France J. The effect of high-sugar grass on predicted nitrogen excretion and milk yield simulated using a dynamic model. J Dairy Sci 2011;94(6):3105-18.

Morvay Y, Bannink A, France J, Kebreab E, Dijkstra J. Evaluation of models to predict the stoichiometry of volatile fatty acid profiles in rumen fluid of lactating Holstein cows. J Dairy Sci 2011;94(6):3063-80.

Strathe, A.B., J. Dijkstra, J. France, S. Lopez, T. Yan, and E. Kebreab. 2011. A Bayesian approach to analyzing energy balance data from lactating dairy cows. J. Dairy Sci., 94:2520-2531.

Neijat M, House JD, Guenter W, Kebreab E. Production performance and nitrogen flow of Shaver White layers housed in enriched or conventional cage systems. Poult Sci 2011;90(3):543-54.