Edge University of Guelph Guelph, Ontario, Canada Introduction The dry period is a crucial phase in the lactation cycle of a dairy cow. Dairy managers aim to dry off pregnant cows to achieve a dry period of appropriate length to maximise productivity in the next lactation (5,6,7,17,19).The herd average dry period length is correlated with herd average milk production (12). A dry period of 60 days is considered ideal.s the herd average days dry deviates from 60 days, average milk production of the herd decreases. However, as the genetic potential for milk production continues to increase, it becomes a management challenge to stop milk production in high producing individuals in order to achieve the 60 day goal.