We've been doing some flushing lately. I'm not sure about the cost, I don't deal with that end.
Our cow criteria is this: they have to have had at least 4 top of the line calves in our herd. The 2 cows we have flushed/are flushing this year didn't come out of our herd, but have been in the herd long enough for us to know what they can produce. In these 2 cows especially, we looked at the association's records to see if these cows have been previously flushed. Both had so we figured that was a pretty good indicator of what they can do. We take pretty meticulous records of our herd, so we have good indicators of who are the better cows and who aren't. With cows that we produced, we have a good idea of where they come from. We will not flush a cow who's mom had to leave the farm because of any problem besides old age. We also look at the cow's sire to make sure he is/was up to par. We then take a look back at her calves, what were they sold for as bulls? how many steers has she had? what/how are her daughters doing, and if they still are or aren't in the herd for any reason other than being sold? etc. After all that is looked at, we then take a look at her EPDs and make sure her's are where we want to be (we don't chase numbers, but for some of our customers that sometimes is important). We also take note of how the cow herself is looking, is she at the adequate body condition for her age? does she still overall look 'good'? We also look at the sires her calves were out of, and then from there decide what direction we want to go with the flushing.
Our recip cows have to go under scrutiny too. They have to have raised a good calf, with no problems. We want to make sure that with the time, money, and effort going into the whole ordeal, the recips will perform well also. We don't have a preference as to whether they're purebred or xbred. But the purebreds that get an embryo are usually the ones that are inconsistent with their calves (ie: have had more steers than bulls), so we're not out much money for her raising an ET calf over a AI calf.