The aim of our project is to take a multi-dimensional approach to evaluate the effects of early vs. delayed separation of the postpartum cow and newborn calf on behavior, health, and productivity. Our central hypothesis is that prolonged transition milk feeding alone or in synergy with direct cow-calf social contact affects calf behavior, growth, immune response and the ability to establish a diverse gastrointestinal and respiratory microbiome. We further hypothesize that early vs. delayed separation of the calf affects the behavior and well-being as well as udder health and milkability of the postpartum cow.