Amplitude of the LH secretory episodes was defined
as the relative increase from baseline LH concentrations.
To calculate the point at which the LH surge had
commenced, a method similar to that described by
Roski [21] was used. Briefly, the average LH baseline
concentration was calculated for each gilt using all
samples taken at 12-h intervals, and the standard
deviation around the mean was calculated. The
occurrence of consecutive samples that were two
standard deviations above the LH baseline was then
considered to be the point at which the LH surge had
begun. Once LH concentrations had consistently
declined below this level, the LH surge was deemed
to be complete.