The cow as a model to study food intake regulation.

Animal models have been invaluable for studying aspects of food intake regulation that for various reasons cannot be observed in humans. The dairy cow is a unique animal model because of an unrivaled energy requirement; its great drive to eat results in feeding behavior responses to treatments within the physiological range. Cows' docile nature and large size make them ideal for measuring temporal treatment effects because digestion and absorption kinetics and responses in endocrine systems, gene expression, metabolite pools and fluxes, and feeding behavior can be measured simultaneously. Thus, cows are important models to investigate interactions of short-term signals regulating food intake. Furthermore, different physiological states throughout the lactation cycle provide powerful models to study how short- and long-term signals interact to affect long-term energy status. The use of the cow as a model can lead to breakthroughs in understanding the complex interactions of signals regulating food intake.