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. Nan, Y., Rodas-Gonzalez, A., Stanford, K., Nadon, C., Yang, X., McAllister, T., Narváez-Bravo, C. (2022). Formation and Transfer of Multi-Species Biofilms Containing E. coli O103:H2 on Food Contact Surfaces to Beef. Frontiers in Microbiology, [online] 13 http://dx.doi.org/10.3389/fmicb.2022.863778

    2022 - View publication details

  2. Klassen, L., Reintjes, G., Tingley, J.P., Jones, D.R., Hehemann, J.H., Smith, A.D., Schwinghamer, T.D., Arnosti, C., Jin, L., Alexander, T.W., Amundsen, C., Thomas, D., Amann, R., McAllister, T.A., Abbott, D.W. (2021). Quantifying fluorescent glycan uptake to elucidate strain-level variability in foraging behaviors of rumen bacteria. Microbiome, [online] 9(1), http://dx.doi.org/10.1186/s40168-020-00975-x

    2021 - View publication details

  3. Holman, D.B., Klima, C.L., Gzyl, K.E., Zaheer, R., Service, C., Jones, T.H., McAllister, T.A. (2021). Antimicrobial Resistance in Enterococcus Spp. Isolated from a Beef Processing Plant and Retail Ground Beef. Microbiology Spectrum, [online] 9(3), http://dx.doi.org/10.1128/Spectrum.01980-21

    2021 - View publication details

  4. Nair, J., Lima, P.M.T., Abdalla, A.L., Molnar, L.J., Wang, Y., McAllister, T., and Geddes, C.M. 2021. Kochia (Bassia scoparia) harvest date impacts nutrient composition, in vitro degradability, and feed value more than pre-harvest herbicide treatment or herbicide resistance traits. 2021 American Society of Agronomy (ASA) – Crop Science Society of America (CSSA) – Soil Science Society of America (SSSA) International Annual Meeting Nov 07-10, 2021. Salt Lake City, UT. (Poster Presentation).

    2021 - View publication details

  5. Nordi, W.M., Marti, S., Gellatly, D., Meléndez, D.M., González, L.A., McAllister, T.A., Fierheller, E.E., Caulkett, N.A., Janzen, E., Schwartzkopf-Genswein, K.S. (2020). Effect of preemptive flunixin meglumine and lidocaine on behavioral and physiological indicators of pain post-band and knife castration in 6-mo-old beef calves.. Livestock Science, [online] 230 http://dx.doi.org/10.1016/j.livsci.2019.103838

    2020 - View publication details

  6. Owens, J.L., Thomas, B.W., Stoeckli, J.L., Beauchemin, K.A., McAllister, T.A., Larney, F.J., Hao, X. (2020). Greenhouse gas and ammonia emissions from stored manure from beef cattle supplemented 3-nitrooxypropanol and monensin to reduce enteric methane emissions. Scientific Reports, [online] 10(1), http://dx.doi.org/10.1038/s41598-020-75236-w

    2020 - View publication details

  7. Terry, S.A., Ribeiro, G.O., Conrad, C.C., Beauchemin, K.A., McAllister, T.A., Gruninger, R.J. (2020). Pretreatment of crop residues by ammonia fiber expansion (AFEX) alters the temporal colonization of feed in the rumen by rumen microbes. FEMS Microbiology Ecology, [online] 96(6), http://dx.doi.org/10.1093/femsec/fiaa074

    2020 - View publication details

  8. Ribeiro, G.O., Gruninger, R.J., Jones, D.R., Beauchemin, K.A., Yang, W.Z., Wang, Y., Abbott, D.W., Tsang, A., McAllister, T.A. (2020). Effect of ammonia fiber expansion-treated wheat straw and a recombinant fibrolytic enzyme on rumen microbiota and fermentation parameters, total tract digestibility, and performance of lambs. Journal of Animal Science, [online] 98(5), http://dx.doi.org/10.1093/jas/skaa116

    2020 - View publication details

  9. Ma, Z., Stanford, K., Bie, X.M., Niu, Y.D., McAllister, T.A. (2020). Effects of Beef Juice on Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel. Foodborne Pathogens and Disease, [online] 17(4), 235-242. http://dx.doi.org/10.1089/fpd.2019.2716

    2020 - View publication details

  10. 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

  11. 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

  12. Azad, E., Derakhshani, H., Forster, R.J., Gruninger, R.J., Acharya, S., McAllister, T.A., Khafipour, E. (2019). Characterization of the rumen and fecal microbiome in bloated and non-bloated cattle grazing alfalfa pastures and subjected to bloat prevention strategies. Scientific Reports, [online] 9(1), http://dx.doi.org/10.1038/s41598-019-41017-3

    2019 - View publication details

  13. Terry, S.A., Redman, A.A.P., Ribeiro, G.O., Chaves, A.V., Beauchemin, K.A., Okine, E., McAllister, T.A. (2019). Effect of a pine enhanced biochar on growth performance, carcass quality, and feeding behavior of feedlot steers. Translational Animal Science, [online] 4(2), http://dx.doi.org/10.1093/tas/txaa011

    2019 - View publication details

  14. 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

  15. Terry, S.A., Ribeiro, G.O., Gruninger, R.J., Chaves, A.V., Beauchemin, K.A., Okine, E., McAllister, T.A. (2019). A Pine Enhanced Biochar Does Not Decrease Enteric CH4 Emissions, but Alters the Rumen Microbiota. Frontiers in Veterinary Science, [online] 6 http://dx.doi.org/10.3389/fvets.2019.00308

    2019 - View publication details

  16. Gruninger, R.J., Ribeiro, G.O., Cameron, A., McAllister, T.A. (2019). Invited review: Application of meta-omics to understand the dynamic nature of the rumen microbiome and how it responds to diet in ruminants, 13(9), 1843-1854. http://dx.doi.org/10.1017/S1751731119000752

    2019 - View publication details

  17. Zaheer, R., Lakin, S.M., Polo, R.O., Cook, S.R., Larney, F.J., Morley, P.S., Booker, C.W., Hannon, S.J., Van Domselaar, G., Read, R.R., McAllister, T.A. (2019). Comparative diversity of microbiomes and Resistomes in beef feedlots, downstream environments and urban sewage influent. BMC Microbiology, [online] 19(1), http://dx.doi.org/10.1186/s12866-019-1548-x

    2019 - View publication details

  18. Klima, C.L., Holman, D.B., Ralston, B.J., Stanford, K., Zaheer, R., Alexander, T.W., McAllister, T.A. (2019). Lower Respiratory Tract Microbiome and Resistome of Bovine Respiratory Disease Mortalities. Microbial Ecology, [online] 78(2), 446-456. http://dx.doi.org/10.1007/s00248-019-01361-3

    2019 - View publication details

  19. Nair, J., Turkington, T.K., Blackshaw, R., Geddes, C.M., Lupwayi, N.Z., Xu, S., Yang, J., Yang, H.E., Wang, Y., McAllister, T.A. (2019). Impact of field fungal contamination of barley on ensiling properties, nutritional quality and the microbiome of barley silage. Grass and Forage Science, [online] 74(2), 231-243. http://dx.doi.org/10.1111/gfs.12419

    2019 - View publication details

  20. He, Z.X., Ribeiro, G.O., Beauchemin, K.A., McAllister, T.A., Yang, W.Z. (2019). Inoculum source and transfer of rumen contents from bison to cattle improved in vitro gas production and feed digestibility, but not the responses to exogenous enzymes supplementation. Animal Feed Science and Technology, [online] 248 37-46. http://dx.doi.org/10.1016/j.anifeedsci.2019.01.005

    2019 - 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;