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Ron Lewis

Professor

Animal Genetics


Ph.D. Animal Science, May 1990, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

M.S. Animal Breeding, August 1986, Texas A&M University, College Station, Texas, USA

B.S. Animal Science, June 1981, University of California, Davis, California, USA

 

My teaching focus is on leading a national graduate-level distance-delivery curriculum integrating quantitative genetics and genomics in animal breeding.  In addition, I continue developing an online game (CyberSheep) to provide experiential learning in undergraduate and graduate instruction in animal genetics.

 

Undergraduate Courses Taught:

Animal Breeding and Genetics (ALS 3104)

 

Graduate:

Coordinator of Engaging the New Biology: integrating quantitative genetics and genomics in animal breeding graduate learning, a national graduate-level distance delivery program.

 

Graduate Courses Taught:

Quantitative Genetics Applications of Matrix Algebra (ALS 5504)

History and Perspectives in Animal Breeding (APSC 5974; co-instructed with Dr. Matt Spangler, University of Nebraska-Lincoln)

CyberSheep: a Genetic Simulation Game (APSC 5974)

A Primer to Quantitative Genetics (APSC 5974; co-instructed with Dr. Mark Enns, Colorado State University)

Selection Index Theory and Application (APSC 5974)

 

My research interests are in animal breeding and (quantitative) genetics with two main themes:  (i) defining pragmatic strategies to improve the reliability of genetic evaluation, and thereby enhancing selection response, in livestock species; and, (ii) understanding how animals, changed through artificial selection, are influenced by and interact with their environment.  This work involves a mixture of theory, simulation and field studies, with close collaborations nationally, in Great Britain and in Norway. 

Research projects in these themes that I currently have underway are: (i) enhancing the reliability of genetic evaluations in ruminant livestock by developing strategies to ensure strong genetic links (connectedness) across-farms; (ii) assessing genetic sensitivities to nutritional constraints and disease challenges in long-term divergently selected lines of chickens; (iii) testing the efficacy of index selection in terminal sire breeds of sheep for improving performance of their crossbred offspring; and, (iv) predicting intake and diet selection in unrestrained (grazing) cattle, and evaluating behavior in young cattle predictive of future temperament in the breeding herd.

List of Publications since 2008

In the following list of refereed publications, an ‘*’ indicates that the publication was a collaboration with a current or former graduate student, or post-doctoral student.

  1. Albrecht, H. N.*, P. B. Siegel, F. W. Pierson, and R. M. Lewis. 2012. Egg quality traits differ in hens selected for high as compared to low antibody response to sheep red blood cells. Poult. Sci. 91:3025–3031.
  2. Albrecht, H. N.*, P. B. Siegel, F. W. Pierson, M. L. McGilliard, and R. M. Lewis. 2012. Reproductive soundness is higher in chickens selected for low as compared to high antibody response. Poult. Sci. 91:1796–1803.
  3. Blevins, S.*, P. B. Siegel, D. J. Blodgett, M. Ehrich, and R. M. Lewis. 2012. Liver enzymes in White Leghorns selected for the SRBC immune response.  Poult. Sci. 91:322–326.
  4. Márquez, G. C.*, W. Haresign, M. H. Davies, G. C. Emmans, R. Roehe, L. Bünger, G. Simm, and R. M. Lewis. 2012. Index selection in terminal sires improves early lamb growth. J. Anim. Sci. 90:142–151.
  5. Márquez, G. C.*, W. Haresign, M. H. Davies, R. Roehe, L. Bünger, G. Simm, and R. M. Lewis. 2012. Index selection in terminal sires improves lamb performance at finishing. J. Anim. Sci. (Accepted).
  6. Bhatnagar, A. S.*, R. M. Lewis, D. R. Notter, C. Schacht, and R. K. Splan. 2011. Genetic parameters of foal inspection scores for two North American sporthorse registries. Livest. Sci. 140:88-94.
  7. Blevins, S.*, P. B. Siegel, D. J. Blodgett, M. Ehrich, G. K. Saunders, and R. M. Lewis. 2010. Effects of silymarin on gossypol toxicosis in divergent lines of chickens. Poult. Sci. 89:1878-1886.
  8. Emenheiser, J. C.*, S. P. Greiner, R. M. Lewis, and D. R. Notter. 2010. Validation of live animal ultrasonic measurements of body composition in market lambs. J. Anim. Sci. 88:2932-2939.
  9. Emenheiser, J. C.*, S. P. Greiner, R. M. Lewis, and D. R. Notter. 2010. Longitudinal changes in ultrasonic measurements of body composition during growth in Suffolk ram lambs, and evaluation of alternative adjustment strategies for ultrasonic scan data. J. Anim. Sci. 88:1341-1348.
  10. Lewis, R. M., and G. C. Emmans. 2010. Feed intake of sheep as affected by live weight, genotype, breed and feed composition. J. Anim. Sci. 88:467-480.
  11. Márquez, G. C.*, P. B. Siegel, and R. M. Lewis. 2010. Genetic diversity and population structure in lines of chickens divergently selected for high and low eight-week body weight. Poult. Sci. 89:2580-2588.
  12. Mekkawy, W.*, R. Roehe, R. M. Lewis, M. H. Davies, L. Bünger, G. Simm, and W. Haresign. 2010. Comparison of repeatability and multiple trait threshold models for litter size in sheep using observed and simulated data in Bayesian analyses. J. Anim. Breed. Genet. 127:261-271.
  13. Sawalha, R.*, M. B. Villanueva, S. Brotherstone, P. L. Rogers, and R. M. Lewis. 2010. Prediction of prion protein genotype and association of this genotype with lamb performance traits of Suffolk sheep. J. Anim. Sci. 88:428-434.
  14. Kuehn, L. A.*, R. M. Lewis, and D. R. Notter. 2009. Connectedness in Targhee and Suffolk flocks participating in the U.S. National Sheep Improvement Program. J. Anim. Sci. 87:507-515.
  15. Macfarlane, J. M.*, R. M. Lewis, G. C. Emmans, M. J. Young, and G. Simm. 2009. Predicting tissue distribution and partitioning in terminal sire sheep using X-ray computed tomography. J. Anim. Sci. 87:107-118.
  16. Man, W.-Y. N.*, N. Nicholls, M. E. J. Woolhouse, R. M. Lewis, and B. Villanueva. 2009. Evaluating different PrP genotype selection strategies for expected severity of scrapie outbreaks and genetic progress in performance in commercial sheep. Prev. Vet. Med. 91:161-171.
  17. Mekkawy, W.*, R. Roehe, R. M. Lewis, M. H. Davies, L. Bünger, G. Simm, and W. Haresign. 2009. Genetic relationship between longevity and objectively or subjectively assessed performance traits in sheep using linear censored models. J. Anim. Sci. 87:3482-3489.
  18. Kuehn, L. A.*, D. R. Notter, and R. M. Lewis. 2008. Assessing genetic gain, inbreeding, and bias due to different flock genetic means in alternative sheep sire referencing schemes J. Anim. Sci. 86:526-535.
  19. Kuehn, L. A.*, D. R. Notter, G. E. Nieuwhof, and R. M. Lewis. 2008. Changes in connectedness over time in alternative sheep sire referencing schemes. J. Anim. Sci. 86:536-544.
  20. Wolf, B. T., K. Howells, C. Nakielny, W. Haresign, R. M. Lewis, O. Davies, and M. H. Davies. 2008. Genetic parameters for strongyle and Nematodirus faecal egg counts in lambs and their relationships with performance traits. Livest. Sci. 113:209-217.
  21. Wolf, B. T., S. D. McBride, R. M. Lewis, M. H. Davies, and W. Haresign. 2008. Estimates of the genetic parameters and repeatability of behavioural traits of sheep in an arena test.  Appl. Anim. Behav. Sci. 112:68-80.
    Ron Lewis

  • (540) 231-1906
  • (540) 231-3010 (Fax)
  • (540)231-9189 (Lab)
  • (540) 231-4868 (Lab)
  • rmlewis@vt.edu
  • Animal and Poultry Sciences (0306)
    3100 Litton Reaves Hall, Virginia Tech
    175 West Campus Dr.
    Blacksburg, VA 24061