No...embryos cannot be "flushed" - aka recovered - until a minimum of 6 days after ovulation; at that point they travel down into the uterine horn and can be recovered. Maximum of 9 days. The recipient cow MUST be an exact number of days that corresponds to the donor cow, because the recip must have the right uterine environment for that embryo, and there's a big difference in the uterine environment 4 days after estrus and 8 days after estrus.
What IS a waste of money is AIing the recip cow on her heat - there is absolutely NO need for it, and while it may increase your chance of getting a calf from that heat (65% conception rate for embryos), it also increases the chance of getting TWINS - and what if you end up with a bull-heifer set??? besides all the complications that come with twins, like retained placentas and uterine infections and the like.
If you're going to AI the cow, then AI her and wait 21 days and hope she settles. If you're going to put an embryo in, then do that at the right time, but good grief, don't bother doing BOTH!
Jeanne- I think what glover means is that the cow in the picture was an embryo herself, years ago, that had been purchased as such and then put into a recip cow.