Successful recipient cows?

I was wondering what everybody's experience has been  with recipient cows  with
using recip's that have successfully stuck in past years versus those that have not?

I had 10 embryos implanted last year in my own recips and 5 stuck and 5 did not.
No variance in age, nutrition, or condition of the cows being used.
I was wondering if some cows are just harder to get an implanted egg to stick versus others?
I am going to have another 10-12 embryos put  in this summer again and was wondering if
it is wise to use those recips from last year that didn't work?

I know I have seen form past AI experience that some cows always seem to settle AI
and some don't. Maybe it could be an individuals timing as to when it puts out the egg and
could be earlier or later than normal.  I don't have any documented proof but It also seems like
cows that come from generations of AI also are easier to settle AI.  Is there
some positive trait there that is inadvertently being selected for?  Is this also true for embryo
recipients, that some just seem to work and others don't.  This is only my second year of ET and
was wondering if the cows that didn't stick last year should be avoided? Any input will
be appreciated.

I like to use some of my best cows for recips.  The ones that breed first service, raise a big calf and have good dispostions.  Last year I kept some spring calving 1st calf heifers open and put embryos in them in November.  All of them are now safe with the embryos. 

My Uncle and Cousin, who runs a very large recep herd and has for many years, have found absolutely no correlation between a cow accepting an embryo one year and not another.
A cow that accepts an embryo one year, has no greater chance doing it the following year, nor does one that does not accept an embryo increases her odds of not accepting one the following year.
So, no, in their experience there is no increase or decrease in chance given a history of a cow.
Strange but true.

Thanks Show Heifer, thats good to know coming from a herd that has
alot of history working with recips.

Last year I used what I consider to be one of my most fertile cows
(never misses AI) for a recip and put one of my best embryos in her
thinking it was a sure thing and she didn't stick.  Luck of the draw I guess.
I will use her again this year and give her a chance to redeem herself.

A lot of it depends on the egg.  Even if the cow is ready, the egg might have been damaged in the freezing or the thawing process.  It can get pretty frustrating, putting one egg is is a little different than putting in a few million sperm.  Good luck, it is not always the cows fault.

I was told once by an ET tech that if recip fails 3 years in a row under normal circumstances that you should just move on and take them out of the recip program. I have had some take every single year and others that never took once, and everywhere in between.