How old to breed a Dexter heifer?

Someone sent an email this week asking about how early they should breed their heifer and I also received a phone from a breeder wanting to know when she could let her bull out with her heifers. While bulls have been known to jump the fence and breed a Dexter heifer as young as five months old, you want to try to avoid this. This long time Dexter breeder's advice is what I've followed:

"A heifer can be bred at 9 mos. We had a heifer that had her first calf at 18 months and 9 or 10 days. However it might be better to have the calf arrive when the dam is 24 months old. I would say it's your choice when to breed."

So while ideally you may want your heifer to calf at 24 months of age, generally if she calves at 18 months or older you should be okay.