The splanchnic tissues of cattle are comprised of the portal-drained viscera (PDV; the gastrointestinal tract, pancreas, spleen, and associated adipose) and the liver. The PDV and liver act as an anatomically and functionally integrated unit which monitors the flow of nutrients from the diet and integrates their metabolism with body requirements. This integration occurs via a myriad of orchestrated metabolic, neural, and endocrine signals which through interplay with the brain ultimately determine appetite, digestive function and the balance between nutrient availability and use for productive function. This review will focus on specific aspects of endocrine metabolism by these tissues in cattle, and consider their potential impact on nutrient intake during lactation.