The transition period is critical in milk production. We are aware of the complications that can occur in dairy production on the farm when we do not work properly. What is the transition period? This transition period ranges from 30 days or 21 days for the pre-calving cow to 60 or 90 days post-calving for that cow. It's a period between 90 days and 100 days that I have to be more careful with the cow.