Research efforts in my laboratory are multifaceted but focused on several aspects of productive efficiency of primarily dairy cattle. With increasing pressure on the dairy industry to reduce the environmental impact of cattle, we are currently working on developing a basic understanding of whole animal nitrogen metabolism and efficiency of use of absorbed amino acids. We have embarked on several studies employing stable isotopes of nitrogen compounds to understand urea nitrogen recycling and the ultimate fate of intake nitrogen. This work is leading to new dietary strategies that allow nutritionists to reduce the amount of nitrogen (crude protein) fed to lactating cows while maintaining milk production thus improving the efficiency of use of absorbed feed nitrogen and reducing the amount of manure nitrogen excreted into the environment per unit of milk produced. Data from studies like this are being used further develop the Cornell Net Carbohydrate and Protein System (CNCPS).
My group is furthering this work with new studies examining the role of carbohydrate digestion and site of digestion on the partitioning of those substrates to milk. This has direct effects on the overall efficiency of the animal and how absorbed amino acids are utilized. We are embarking on studies that allow us to further describe the efficiency of use of absorbed amino acids with the goal of further enhancing the efficiency of use of protein by the lactating dairy cow.
In support of the CNCPS, we are also developing new tools to describe how NDF digestion occurs in various feeds. Our focus is primarily forages and our goal is to better describe the rate and extent of NDF digestion for use in the model with the objective of linking this to dry matter intake and whole farm forage allocation to reduce the importation of non-farm raised feeds, thus reducing the importation of nutrients such as phosphorous and nitrogen.
Finally, the lab has a 15 year history of engaging in research to enhance our understanding of the nutrient requirements and management of calves and heifers. Previous work identified time and not nutrient intake as the primary factor influencing pre-pubertal mammary development as measured by DNA. This has significant implications for years of research into this very perplexing and controversial issue and allows us to redirect of efforts on factors that can be manipulated and have a larger impact on future milk potential. To that point, recent work has strongly demonstrated that early life nutrient intake and growth rates prior to weaning have an epigenetic or imprinting effect on the animal that results in greater milk yield in, a minimum, the first lactation. Further, in collaboration a some colleagues, we were able to demonstrate that pre-weaning growth rates accounted for up to 25% of the variation in first lactation milk production. This is a significant finding and one that provides us with a new direction and with profound implications for early life management of calves and heifers.
Tylutki, T.P., D.G. Fox, V.M. Durbal, L.O. Tedeschi, J.B. Russell, M.E. Van Amburgh, T.R. Overton, L.E. Chase and A.N. Pell. 2007. Cornell Net Carbohydrate and Protein System: A model for precision feeding of dairy cattle. Animal Feed Science and Technology, Volume 143:174 – 202.
S. A. Bascom, R. E. James, M. L. McGilliard, and M. Van Amburgh. 2007. Influence of dietary fat and protein on body composition of Jersey bull calves. J Dairy Sci. 90:5600-5609.
M J Meyer, R P Rhoads, A V Capuco, E E Connor, A Hummel, Y R Boisclair, and M E Van Amburgh. 2007. Ontogenic and nutritional regulation of steroid receptor and IGF-I transcript abundance in the prepubertal heifer mammary gland. J. Endocrinol. 195:59 - 66.
R P Rhoads, J W Kim, M E Van Amburgh, R A Ehrhardt, S J Frank, and Y R Boisclair. 2007
Effect of nutrition on the GH responsiveness of liver and adipose tissue in dairy cows
J. Endocrinol. 195:49 - 58.
Thorn, S. R., M. J. Meyer, M. E. Van Amburgh, and Y. R. Boisclair. 2007. Effect of Estrogen on Leptin and Expression of Leptin Receptor Transcripts in Prepubertal Dairy Heifers
J Dairy Sci. 90:3742-3750.
Borderas, F., M. A. G. von Keyserlingk, D. M. Weary, J. Rushen, A. M. de Passillé, and M. E. Van Amburgh. 2007. Letter to the Editor: The effects of force-feeding sick dairy calves: A comment on Quigley et al. (2006). J Dairy Sci. 90: 3567-3568.
E. E. Connor, M. J. Meyer, R. W. Li, M. E. Van Amburgh, Y. R. Boisclair, and A. V. Capuco. 2007. Regulation of gene expression in the bovine mammary gland by ovarian steroids. J Dairy Sci. 90: E55-65E.
Meyer, M. J., A. V. Capuco, D. A. Ross, L. M. Lintault, and M. E. Van Amburgh. 2006. Developmental and Nutritional Regulation of the Prepubertal Bovine Mammary Gland: II.
Allometric growth, epithelial cell proliferation, and the influence of age at slaughter on
parenchyma development. J Dairy Sci. 89:4298-304
Meyer, M. J, A. V. Capuco, D. A. Ross, L. M. Lintault, and M. E. Van Amburgh. 2006. Developmental and Nutritional Regulation of the Prepubertal Heifer Mammary Gland: I.
Parenchyma and fat pad mass and composition. J Dairy Sci. 89:4289-97.
Meyer, M J, A V Capuco, Y R Boisclair and M E Van Amburgh. 2006 Estrogen-dependent responses of the mammary fat pad in prepubertal dairy heifers. J. of Endocrinology. 190: 819–827
Li R W, Meyer M J, Van Tassell CP, Sonstegard T S, Connor EE, Van Amburgh M E, Boisclair Y R, Capuco, A V. 2006. Identification of estrogen-responsive genes in the parenchyma and fat pad of the bovine mammary gland by microarray analysis. Physiol Genomics.27:42-53
Daniels KM, Webb KE Jr, McGilliard ML, Meyer MJ, Van Amburgh ME, Akers RM 2006. Effects of body weight and nutrition on mammary protein expression profiles in Holstein heifers. J Dairy Sci. 89:4276-4288.
Albrecht, G.L., Q.M. Ketterings, K.J. Czymmek, M. van Amburgh, and D.G. Fox. 2006. Whole Farm Nutrient Management: A capstone course preparing seniors for environmental management of dairy farms. Journal of Natural Resources and Life Science Education 35: 12-23
T. R. Callaway, J. E. Keen, T. S. Edrington, L. H. Baumgard, L. Spicer, E. S. Fonda, K. E. Griswold, T. R. Overton, M. E. Van Amburgh, R. C. Anderson, K. J. Genovese, T. L. Poole, R. B. Harvey, and D. J. Nisbet. 2005. Fecal Prevalence and Diversity of Salmonella Species in Lactating Dairy Cattle in Four States. J. Dairy Sci. 88: 3603-3608.
J. C. Marini and M. E. Van Amburgh. 2005. Partition of Nitrogen Excretion in Urine and the Feces of Holstein Replacement Heifers. J. Dairy Sci. 88: 1778-1784.
Van Amburgh, M. E. and J. K. Drackley. 2005. Current perspectives on the energy and protein requirements of the pre-weaned calf. Chapter 5. In Calf and heifer rearing: Principles of rearing the modern dairy heifer from calf to calving. Nottingham University Press. Ed. P. C. Garnsworthy.
Keene, B.E., K. F. Knowlton, M. L. McGilliard, L. A. Lawrence, S. M. Nickols-Richardson, J. H. Wilson, A. M. Rutledge, L. R. McDowell and M. E. Van Amburgh. 2004. Measures of Bone Mineral Content in Mature Dairy Cows. J. Dairy Sci. 87:3816-3825.
Marini J. C., J. D Klein, J. M. Sands, and M. E. Van Amburgh. 2004. Effect of nitrogen intake on nitrogen recycling and urea transporter abundance in lambs. J Anim Sci. 82:1157-64.
Fox, D.G., Tylutki, T.P, Tedeschi, L.O., Van Amburgh, M. E., Chase, L. E., Pell, A. P., Overton, T. R., and Russell, J. B. 2003. The Net Carbohydrate and Protein System model for evaluating herd nutrition and nutrient excretion. Anim. Sci. Feed Tech. 112:29-78.
Nonnecke, B. J., M. R. Foote, J. M. Smith, B. A. Pesch, and M. E. Van Amburgh. 2003. Composition and Functional Capacity of Blood Mononuclear Leukocyte Populations from Neonatal Calves on Standard and Intensified Milk Replacer Diets. J. Dairy Sci. 86: 3592-3604.
Block, S. S., R. P. Rhoads, D. E. Bauman, R. A. Ehrhardt, M. A. McGuire, B. A. Crooker, J. M. Griinari, T. R. Mackle, W. J. Weber, M. E. Van Amburgh, and Y. R. Boisclair. 2003. Demonstration of a Role for Insulin in the Regulation of Leptin in Lactating Dairy Cows. J. Dairy Sci. 86: 3508-3515.
Block, S. S., J. M. Smith, R. A. Ehrhardt, M. C. Diaz, R. P. Rhoads, M. E. Van Amburgh, and Y. R. Boisclair. 2003. Nutritional and developmental regulation of plasma leptin in dairy cattle. J. Dairy Sci. 86: 3206-3214.
Vicini, J. L., H. G. Bateman, M. K. Bhat, J. H. Clark, R. A. Erdman, R. H. Phipps, M. E. Van Amburgh, G. F. Hartnell, R. L. Hintz, and D. L. Hard. 2003. Effect of feeding supplemental fibrolytic enzymes or soluble sugars with malic acid on milk production. J. Dairy Sci. 2003 86: 576-585.
Marini, J. C. and M. E. Van Amburgh. 2003. Nitrogen metabolism and recycling in Holstein heifers. J. Anim Sci. 2003 81: 545-552.
Marini, J. C. K. W. Simpson, A. Gerold, M. E. Van Amburgh. 2003. The effect of immunization with jackbean urease on antibody response and nitrogen recycling in mature sheep. Livstock Prod. Sci. 81: 283-292.