Jamie -- every one here that knows me, will know that I only breed the donors ONE time, with two units of semen, deposited into the uterin horn a little ways up.
Timing is absolutely EVERYTHING, even if some of these guys breed several times, you are only going to get the fertilization you need if done at the RIGHT time.
When I am asked to flush to two different bulls, it is pretty easy really. I simply place one bull (1 unit ) in the left horn, and the other side getts the other bull. For one thing, if the timing was not correct, you would get all ALL unfertilized no matter what you did. Forget the early breedings, especially shortly after first standing or during standing, you are asting your time and semen. I breed the cows almost every time at least 6 hours AFTER they get done standing, and are tired of it all.
When we go to flush this way, all you have to do is have your facility change filters on each horn, assuming they actually flush each horn seperately ( the most accurate way to get all of the eggs). Once you do this, you will see the difference from one bull or the other. I would bet you, if done this way and both bulls going into different horns at the same time, you will not see the same variance in fertile eggs. I've done it for years, it works good! At birth, I have yet to see a calf from one of the bulls not be what was expected as far as sire. Maybe I am just lucky, but done right, it works well!
Good luck Freddy and every one else!
Terry
