My heifer is due to calve on Aug. 16th. I've read it can come up to 10 days early for 1st timers, is there also a good chance it could come late or would that be more rare? Her bag keeps filling up, but no leaking from the teats. I don't want to squeeze them as it has been muddy (thank God for the last 2 days of sunshine drying things up) and I don't want to open her teats and invite crud in. Is there a chance she can get mastitis before the calf is born? Her teats are swelling up (I guess that is what the books call filling up with milk), but I am unsure if she could already have a touch of mastitis or if this is what the udder and teats should look like before birth. Sorry to be so green, but if I don't ask I won't learn. Thanks.