If you are going to have the vet breed the heifer, you need to check his schedule as to when he would be available. If he is like most that is next to impossible. Start with keeping up with the heifers cycle dates and if she is like most on a 21 day average, just see that she is not coming in on Saturday night and the vet is in church on Sunday morning. A little bit of planning can have the heifer ready to breed on a certain day of the week and a lot less chance of the vet being gone. I am not a real big fan of vets doing the work, first they don't do many, second, they are sometimes of the opinion if she gets bred fine, if not, my bad try again in 3 weeks. I would aim for waiting10 days or so after heat and giving a lutalayse shot in the evening so you could expect heat in the evening and the vet would have overnight alert to be ready. Not a lot of use doing the whole 9 yards if she is predictable on the next heat.