KNERSIE
Re:
If used for abortion its only effective from about 7 days after conception and best results will be before 100 days, after about 150 days it may result in damage to the reproductive tract when the aborted foetus is passed.
Now I'm not trying to put words in your mouth and if I am reading and understanding what you are saying correctly, and please feel free to correct if I am wrong, what you are saying is:
After 7 days of inception the abortion shot is effective? Prior to that it is not?
Its only effective if there is a viable corpus luteum or a viable corpus luteum of pregnancy. That is usually from about 5-6 days after ovulating. The recommendation is to wait atleast 7 days (preferably 10) to be sure there is a viable corpus luteum.
After about 150 days it is still effective but may result in damage to the reproductive tract correct?
Yes, but I think its efficacy goes down as the gestation progresses, but don't quaote me on that.
Assuming we are not concerned about the reproductive track, as this heifer is going to the feed lot as beef, it is still effective, for how long? Up to 30 days prior to giving birth, when you should be able to tell she is spring?
SL