Bio
Professional Interests:
My research program is focused on two key areas: 1) nutrition and metabolism of dairy cows during the dry period and transition to lactation, and 2) early calf nutrition with emphasis on protein and energy requirements for efficient lean growth.
Biology of Periparturient Dairy Cows
The periparturient or transition period is the most critical phase of the lactation cycle, as this is when most health problems occur and cows either get off to a smooth start to milk production or struggle with poor performance and efficiency. Our research into nutrition and management of dry cows has led to the exciting discovery that a controlled energy program, in which cows consume a bulky low-energy, high-straw diet ad libitum, leads to more favorable transition outcomes. In earlier studies we showed that these diets cause metabolic adaptations in liver; therefore, it seemed logical that the adaptations would be accompanied by changes in gene expression. I partnered with Harris Lewin in our Department to write a USDA-NRI grant that was funded in 2001 to initiate our program of Nutritional Genomics of dairy cattle. Dr. Loor was hired as a postdoctoral associate under that program and has conducted groundbreaking microarray studies of liver, adipose tissue, and mammary gland during the transition period. His research showed that during the transition to lactation the liver undergoes marked changes in expression of many genes, many of which begin to change before the hormonal and nutritional changes around calving. More exciting, however, is the finding that plane of nutrition during the dry period influences these gene expression changes. Overfeeding during the dry period results in huge changes in gene expression in the liver relative to controlled energy intake.
Going forward, we aim to establish the role of the internal adipose tissue depots in signaling positive or negative adaptations in the liver, as well as to determine the role of inflammatory-type processes in the liver during successful and turbulent transitions. Functional genomics approaches will be an important component of this research.
Nutrition and Growth in Dairy Calves
The early life period of calves constitutes the period of most efficient skeletal and muscular growth of cattle. However, this growth potential traditionally has not been exploited in dairy calves. We have determined relationships between protein and energy on growth and body composition in neonatal dairy calves. Increased energy intake allows greater growth rates, but this must be matched by appropriate intakes of high-quality protein to fuel lean tissue growth without fattening. We have theorized that more biologically appropriate growth in young calves should promote better health and increase lifetime productivity as those calves become productive cows. Toward this hypothesis, we are beginning to use microarray and real-time RT-PCR techniques to explore whether early nutrition impacts expression of genes that influence growth, health, and body composition.
Recent publications:
Drackley, J. K. 2006. Advances in transition cow biology: New frontiers in production diseases. Keynote address. In Proceedings XII International Conference on Production Diseases in Farm Animals. N. Joshi and T. H. Herdt, ed. Wageningen Academic Publishers, Wageningen, The Netherlands. (in press).
Dann, H. M., N. B. Litherland, J. P. Underwood, M. Bionaz, A. D’Angelo, J. W. McFadden, and J. K. Drackley. 2006. Diets during far-off and close-up dry periods affect periparturient metabolism and lactation in multiparous cows. Journal of Dairy Science 89:(in press).
Bartlett, K. S., F. K. McKeith, M. J. VandeHaar, G. E. Dahl, and J. K. Drackley. 2006. Growth and body composition of dairy calves fed milk replacers containing different amounts of protein at two feeding rates. Journal of Animal Science 84:(in press).
Drackley, J. K.,R. M. Blome, K. S. Bartlett, and K. L. Bailey. 2006. Supplementation of 1% L-glutamine to milk replacer does not overcome the growth depression in calves caused by soy protein concentrate. Journal of Dairy Science 89:(in press).
Drackley, J. K., S. S. Donkin, and C. K. Reynolds. 2006. Major advances in fundamental dairy cattle nutrition. Journal of Dairy Science. 89:1324-1336. (Invited review – JDS Centennial edition).
Drackley, J. K., and J. B. Andersen. 2006. Splanchnic metabolism of long-chain fatty acids in ruminants. In Ruminant Physiology: Digestion, Metabolism and Impact of Nutrition on Gene Expression, Immunology and Stress. K. Sejrsen, T. Hvelplund and M.O. Nielsen, ed. Proceedings 10th International Symposium on Ruminant Physiology, Copenhagen, DK. Wageningen Academic Publishers, Utrecht, Netherlands.
Drackley, J. K., H. M. Dann, G. N. Douglas, N. A. Janovick Guretzky, N. B. Litherland, J. P. Underwood, and J. J. Loor. 2005. Physiological and pathological adaptations in dairy cows that may increase susceptibility to periparturient diseases and disorders. Italian Journal of Animal Science 4:323-344. (Invited review)
Dann, H. M., and J. K. Drackley. 2005. Carnitine palmityoltransferase I in liver of periparturient dairy cows: effects of prepartum intake, postpartum induction of ketosis, and periparturient disorders. Journal of Dairy Science 88:3851-3859.
Loor, J. J., H. M. Dann, R. E. Everts, R. Oliveira, C. A. Green, N. A. Janovick-Guretzky, S. L. Rodriguez-Zas, H. A. Lewin, and J. K. Drackley. 2005. Temporal gene expression profiling of liver from periparturient dairy cows reveals complex adaptive mechanisms in hepatic function. Physiological Genomics 23:217-226.
Dann, H. M., D. E. Morin, M. R. Murphy, G. A. Bollero, and J. K. Drackley. 2005. Prepartum intake, postpartum induction of ketosis, and periparturient disorders affect the metabolic status of dairy cows. Journal of Dairy Science. 88:3249-3264.
Douglas, G. N., T. R. Overton, H. G. Bateman II, and J. K. Drackley. 2004. Peripartal metabolism and production of Holstein cows fed diets supplemented with fat during the dry period. Journal of Dairy Science. 87:4210-4220.
Blome, R. M., J. K. Drackley, F. K. McKeith, M. F. Hutjens, and G. C. McCoy. 2003. Growth, nutrient utilization, and body composition of dairy calves fed milk replacers containing different amounts of protein. Journal of Animal Science 81:1641-1655.
Grum, D. E., J. K. Drackley, and J. H. Clark. 2002. Fatty acid metabolism in liver of dairy cows fed supplemental fat and nicotinic acid during an entire lactation. Journal of Dairy Science 85:3026-3034.
Drackley, J. K., T. R. Overton, and G. N. Douglas. 2001. Adaptations of glucose and long-chain fatty acid metabolism in liver of dairy cows during the periparturient period. Journal of Dairy Science 84(E. Suppl.):E100-E112. (Invited review)
Drackley, J. K. 1999. Biology of dairy cows during the transition period: the final frontier? Journal of Dairy Science. 82:2259-2273.
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