Tim A. McAllister, Ph. D.

Image Tim A. McAllister
Research Scientist, Ruminant Nutrition & Microbiology

Current research and/or projects


  •  Evaluation of Antimicrobial resistance (AMR) in livestock from a one Health Perspective
  •  Impact of Canadian Beef Cattle Production on Biodiveristy
  •  Role of the Canadian Beef Industry in the maintenance and preservation of carbon stocks in agricultural systems
  •  Impact of performance enhancing technologies on greenhouse gas emissions from beef production systems.
  •  Evaluation of the use of enzymes to enhance the utilization of feeds by ruminants.
  •  Assessment of the potential of Biochar added to beef cattle diets to reduce greenhouse gas emissions in agriculture
  •  Development of methods to control the rate of cereal grain fermentation in beef cattle.
  •  Characterization of the effects of tannins on cellulose digestion in ruminants.
  •  Characterization of the digestive properties of cereal grains in beef cattle.
  •   Evaluation of the role of ruminal fungi in feed digestion in ruminants.
  •   Estimation of greenhouse gas emissions in beef cattle production systems.
  •   Strategies for mitigation of fecal shedding of Escherichia coli O157:H7 by cattle.
  •   Quantification and characterization of methane emissions arising from livestock production.
  •   Composting as a means of disposal of animal carcasses and for containment of biohazardous agents.
  •   Investigation on the stability of  prions in compost
  •   The use of metagenomics to develop mitigation strategies for Escherichia coli O157:H7 colonization in cattle


Research and/or project statements

Antimicrobial resistance (AMR) in livestock from a One Health perspective, strategies for mitigation of  E. coli O157:H7 throughout the beef production chain, including bacteriophage therapy, passive immunotherapy, electrolyzed oxidizing anode water, management strategies, and dietary interventions.  Interactions of microbiomes in food safety, feed quality and enteric methane emissions.  Development of methods to characterize and reduce greenhouse gas emissions from beef cattle production systems in enteric methane emissions, and the implications of land use change for carbon sequestration and biodiversity in beef cattle production systems. Characterization of the digestive properties of cereal grains and the use of by-products in beef cattle diets and development of methods to enhance the ensiling of cereal forages and that value of low quality forages.  Prevention of pasture and feedlot bloat in cattle; composting as a means of disposal of animal carcasses for containment of biohazardous agents; assessing the fate of transgenic DNA ingested by livestock in genetically modified crops used as feeds; characterization of effects of tannins on cellulose digestion by ruminants; potential uses of plant extracts and probiotics as alternatives to antibiotics in livestock production. His collaborations have generated over 800 peer-reviewed scientific publications. 

Education and awards

Ph.D. Ruminant Nutrition / Microbiology (with distinction) (1991) - University of Guelph, Ontario

M.Sc. Animal Biochemistry (1987) - University of Alberta, Edmonton

B.Sc. Agriculture (with distinction) (1985) - University of Alberta, Edmonton  

  • Canadian Society of Animal Science Fellowship Award (2018)

  • Canadian Beef Industry Award for Outstanding Research and Innovation - presented by the Beef Cattle Research Council (BCRC) (2016)

  • H.R. MacMillan Laureate in Agriculture – University of Guelph (2015)

  • Public Service Award of Excellence – Scientific Contribution - Public Service of Canada. The Right Honourable Stephen Harper, Prime Minister of Canada (2014)

  • The Governor General of Canada - Queen Elizabeth II Diamond Jubilee Medal. Nominated by the Canadian Cattlemen’s Association (2012)

  • American Society of Animal Science / American Feed Industry Association Award in Ruminant Nutrition Research (2010)

  • Canadian Society of Animal Science Award for Excellence in Nutrition and Meat Science (2008)

  • Nobel Peace Prize (as a member of the Intergovernmental Panel on Climate Change, which shared this prize with former US Vice-President Al Gore) – awarded for raising international awareness of Greenhouse Gases and Global warming (2007)

  • AAFC Minister’s Gold Harvest Award for 2005 (individual award).

  • Alberta Agriculture Performance Excellence (AAPEX) Award for Outstanding Teamwork – Silver Recipient – for work on the Alfasure Project Research Team (2005)

  • Alberta Agriculture Performance Excellence (AAPEX) Award for Outstanding Teamwork – Silver Recipient – for work on the Biostel Project Research Team (2005)

  • Canadian Society of Animal Science Award for Technical Innovation in Enhancing Production of Safe Affordable Food (2004)

  • AAFC Minister’s Gold Harvest Award (as part of www.foragebeef.ca team) (2003)

  • Canadian Society of Animal Science Canadian Animal Industries Award for Excellence in Extension and Public Service (2000)

  • AAFC Ag Excellence Award for Contribution to Canadian Agriculture (1998)

  • Canadian Society of Animal Science Outstanding Young Scientist Award (1996)

International experience and/or work


  • The Canadian Cattlemen's Association Expert Advisory Committee on E. coli O157:H7(2001- present)

  • Food and Agriculture Organization of the United Nations LEAP (Livestock Environmental Assessment and Performance) Group -The Chair of the Biodiversity Technical Advisory Committee

  • World Health Organization (WHO), member of the expert advisory committee on strategies to reduce Shiga toxin producing E. coli in the food production chain



Key publications

  1. Challis, J.K., Cantin, J.L., Curtis, A.W., Sura, S., Shade, S., Giesy, J.P., McAllister, T.A.,Jones, P.D. and Larney, F.J. 2020. Environmental fate of melengestrol acetate, trenbolone acetate, and ractopamine in beef cattle feedlots Poster Abstr., 57th Annual Alberta Soil Science Workshop, February 19-20, 2020, Lethbridge, AB.

    2020 - View publication details

  2. Carlos M. Romero, Xiying Hao, Jen Owens, Hongjie Zhang, Erasmus Okine, Abby-Ann Redman, Paul Hazendonk, Tim A. McAllister. Enhancement of manure composting by biochar: An emerging benefit to the use of engineered carbon in animal feeding. 57th Alberta Soil Science Workshop. Lethbridge AB, Feb. 18-20, 2020.

    2020 - View publication details

  3. Cameron, A., Zaheer, R., McAllister, T.A. (2019). Emerging Variants of the Integrative and Conjugant Element ICEMh1 in Livestock Pathogens: Structural Insights, Potential Host Range, and Implications for Bacterial Fitness and Antimicrobial Therapy, 10 http://dx.doi.org/10.3389/fmicb.2019.02608

    2019 - View publication details

  4. Terry, S.A., Badhan, A., Wang, Y., Chaves, A.V., McAllister, T.A. (2019). Fibre digestion by rumen microbiota — a review of recent metagenomic and metatranscriptomic studies, 99(4), 678-692. http://dx.doi.org/10.1139/cjas-2019-0024

    2019 - View publication details

  5. Pogue, S.J., Kröbel, R., Janzen, H.H., Beauchemin, K.A., Legesse, G., de Souza, D.M., Iravani, M., Selin, C., Byrne, J., McAllister, T.A. (2018). Beef production and ecosystem services in Canada's prairie provinces: A review, 166 152-172. http://dx.doi.org/10.1016/j.agsy.2018.06.011

    2018 - View publication details

  6. Jen Owens, Xiying Hao, Ben W. Thomas, Jessica L. Stoeckli, Francis J. Larney, Karen A. Beauchemin, Tim A. McAllister. 2018. Do the effects of dietary greenhouse gas inhibitors persist in beef cattle manure during composting and stockpiling? 2018 Joint Meeting of the CGU-CSSS-CIG-CSAFM-ESSSA. June 10-14, 2018. Niagara Falls, ON. Canada.

    2018 - View publication details

  7. Dugan, M.E.R., Vahmani, P., Rolland, D.C., McAllister, T.A., Block, H.C., Proctor, S.D., Guan, L.L., Prieto, N., Aalhus, J.L., Lopez-Campos, O. 2017. Sequential feeding of extruded flaxseed (LinPRO-R) and hay increases the n-3 PUFA biohydrogenation intermediates in longissimus thoracis of steers. ICoMST, Cork, August 13-18, 2017.

    2017 - View publication details

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    2017 - View publication details

  9. Vahmani, P., Rolland, D.C., Mapiye, C., Dunne, P.G., Aalhus, J.L., Juarez, M., McAllister, T.A., Prieto, N., Dugan, M.E.R. (2017). Increasing desirable polyunsaturated fatty acid concentrations in fresh beef intramuscular fat, 12 http://dx.doi.org/10.1079/PAVSNNR201712020

    2017 - View publication details

  10. Dugan, M., López-Campos, O., Aalhus, J.L., Vahmani, P., Prieto, N., Juárez, M., McAllister, T., Stanford, K. Lamb fat composition: the good, the not so good and possibilities for the future. N’ewesletters Winter 2017.

    2017 - View publication details

  11. Foroutan, A., Dugan, M.E.R, Stothard, P., Grant, J., Paradis, F., Guan, L.L., McAllister, T.A., Basu, U., Li, C., and Fitzsimmons, C.J. (2016). "Gene expression differences associated with fatty-acid deposition in beef cattle fed diets with supplemental flaxseed.", XXIV Plant and Animal Genomics Conference, San Diego, CA, USA, January 2016. (Abstract)

    2016 - View publication details

  12. Vahmani, P., D. C. Rolland, T. A. McAllister, H. C. Block, S. D. Proctor, L. L. Guan, N. Prieto, J. L. Aalhus, and M. E. R. Dugan. 2016. 1306 Feeding steers extruded flaxseed and hay in a total mixed ration or sequentially can have substantial effects on beef fat polyunsaturated fatty acids and biohydrogenation intermediates.. J. Anim. Sci. 94(Suppl5):629-630. doi:10.2527/jam2016-1306

    2016 - View publication details

  13. Topp, E., Irwin, R., McAllister, T.A., Lessard, M., Joensuu, J.J., Kolotilin, I., Conrad, U., Stöger, E., Mor, T., Warzecha, H., Hall, J.C., McLean, M.D, Cox, E., Devriendt, B., Potter, A., Depicker, A., Virdi, V., Holbrook, L., Doshi, K., Dussault, M., Friendship, R.M., Yarosh, O., Yoo, H.S., MacDonald, J.D., and Menassa, R. (2016). "The case for plant-made veterinary immunotherapeutics.", Biotechnology Advances. doi : 10.1016/j.biotechadv.2016.02.007

    2016 - View publication details

  14. Noyes, N.R., Yang, X., Linke, L.M., Magnuson, R.J., Cook, S.R., Zaheer, R., Yang, H., Woerner, D.R., Geornaras, I., McArt, J.A., Gow, S.P., Ruiz, J., Jones, K.L., Boucher, C.A., McAllister, T.A., Belk, K.E., Morley, P.S. (2016). Characterization of the resistome in manure, soil and wastewater from dairy and beef production systems, 6 http://dx.doi.org/10.1038/srep24645

    2016 - View publication details

  15. Vahmani, P., Rolland, D. C., McAllister, T. A., Block, H. C., Proctor, S. D., Guan, L. L., Prieto, N. P., Aalhus, J.L. & Dugan, M. E. R. (2016). Feeding steers hay with extruded flaxseed together or sequentially has a profound effect on erythrocyte trans 11-18: 1 (vaccenic acid). Canadian Journal of Animal Science, 96(3), 299-301.

    2016 - View publication details

  16. Sura, S., Degenhardt, D., Cessna, A.J., Larney, F.J., Olson, A.F. and McAllister, T.A. 2016. Transport of three antimicrobials in runoff from windrows of composting beef cattle manure. J. Environ. Qual. 45: 494–502.

    2016 - View publication details

  17. Noyes, N.R., Benedict, K.M., Gow, S.P., Waldner, C.L., Reid-Smith, R.J., Booker, C.W., McAllister, T.A., and Morley, P.S. (2016). "Modeling considerations in the analysis of associations between antimicrobial use and resistance in beef feedlot cattle.", Epidemiology and Infection, 144(6), pp. 1313-1329. doi : 10.1017/S0950268815002423

    2016 - View publication details

  18. Amarakoon, I.D., Sura, S., Zvomuya, F., Cessna, A.J., Larney, F.J., and McAllister, T.A. 2016. Dissipation of antimicrobials in a seasonally-frozen soil following beef cattle manure application. J. Environ. Qual. 45: 1644–1651.

    2016 - View publication details

  19. Amarakoon, I.D., Zvomuya, F., Sura, S., Larney, F.J., Cessna. A.J., Xu, S. and McAllister, T.A. 2016. Dissipation of antimicrobials in feedlot manure compost after oral administration versus fortification after excretion. J. Environ. Qual. 45: 503–510.

    2016 - View publication details

  20. Stanford, K., Harvey, A., Barbieri, R., Xu, S., Reuter, T., Amoako, K.K., Selinger, L.B., Mcallister, T.A. (2016). Heat and desiccation are the predominant factors affecting inactivation of Bacillus licheniformis and Bacillus thuringiensis spores during simulated composting, 120(1), 90-98. http://dx.doi.org/10.1111/jam.12991

    2016 - View publication details

Research facility

5403 1st Avenue South
Lethbridge, AB T1J 4B1


University of Calgary, Faculty of Medicine

University of Alberta,

University of Saskatchewan,

University of Lethbridge, 

University of Manitoba, 

University of Sydney,    

Kwame Nkrumah University of Science & Technology, Kumasi, Ghana,

 University of Calgary, Department of Production Animal Health;