My program addresses the regulation of nutrient use in lactation, growth and pregnancy, with emphasis on lactation in dairy cows. These efforts involve an integration of nutritional, biochemical and endocrinological aspects of metabolic regulation. Both in vivo and in vitro approaches are used with an overall program goal of developing and understanding of the regulation of nutrient utilization which 1) provides a conceptual basis broadly applicable to all physiological states and biology in general, 2) forms the biological basis for specific studies designed to enhance the efficiency of animal production, and 3) provides for an opportunity to design foods derived from animals to be consistent with consumer perceptions and recommendations.