It is safe to tag them within 20 days of birth, or at least before they leave the holding if this occurs before day 20. I had no idea that registration is supposed to take place within seven days of tagging; what happens if you don't observe these timelines?
It's required to tag baby calves by the time they are 20 days old. We tag our calves a week after they are born. After they're tagged, you only have seven days to register them, which can be somewhat stressful if you have a lot of calves.
We like to tag calves the day they are dropped.It is a lot easier to catch and hold on to them at that time. As far as being required by 20 days I have to ask which association is requiring that and the seven days to register them.