Its just fair for the heifer to let her raise a calf before flusing as she may never have a very good calf after she has been flushed. The way the pedigrees in Angus are going you are taking the highest risk today. Do some things to elimate your risk.
For my meger experience with ET calves its still the calf that we see. Of the flushes that I have been interested in on a good flush their maybe two good calves (at the most) the remained are just calves, sometimes poor calves compaired to the herd. Decide what you are going to do build a herd from the gentics you have or sell the Embryos to the dealers in that play that makert. If I was to embryo a cow today I would choose my very best young COW and flush her to a bull from a herd that is breeding cattle that I like. I would never use semen from AI studs as those bulls are used anywhere everywhere. If I was selling ETs I would do the oppisite trying to buy cows that are realted to something up close popular and breed to popular bulls.
I really cringe on putting in a embryo into a reg cow reiept when knowing that cow herself may bring in a good calf bred to the same bull the embryo is sired by.
I am still a sucker though..This fall I bought a ET bred heifer choice of 4 flush mates
this from a internet bidding service. The sale book had a nice photo of her flush mate sister lot A when they came in the ring you could not see the cattle only their backs. Lot A did not show up in the ring lot C sold I bought Lot B and then Lot D sold.
The heifers were out of one of the highest AND proven double pathfinder family availabe. Cow photo and granddam photo about a materinal as they get. When lot B made it here is is about the most direct oppsite of what I thought it would. Still a big growthly heifer but alot different that what I was expecting by all the promtion on her.