We examined P/AI for cows treated with one of the two
GnRH products during a typical Presynch Ovsynch program
that was followed by an Ovsynch program to resynchronize
nonpregnant cows. To our knowledge, this is the largest
trial comparing two products. The result of the logistic
regression procedure was a nonsignificant 2.7 percentage
point difference in P/AI for cows treated with one of the
two products (38.4 1.2 vs. 35.7 1.3; Cystorelin vs. Factrel).
This numeric difference failed to achieve statistical
significance when tested within the logistic regression
model. The unadjusted raw means for P/AI were 37.4%