In this webinar Dr. Mario Mondaca will discuss baffles in negative pressure ventilation systems for adult dairy cows. We will review the overall design philosophy behind baffles and the history of cross-ventilated barns, the type of barns that most commonly use baffles. We will also look at the latest research on baffle design and position on cross-ventilated barns as well as tunnel-ventilated barns. Finally, we will address unintentional baffles that deflect air away from the animal occupied zone like waterers, concrete walls, cross-over walls, feed bunks, etc. We will review examples from measurements on farms as well as computational fluid dynamics models.