The probe should be inserted at the same angle as an A-I tube.
About a 45% angle. When you reach resistance
turn the probe 180 degrees to insure mucus covers
the end of the probe. Take the reading while the probe is inserted.
Chart your readings and you will know exactly when to breed.
This graft shows typical curve during heat!

Characteristic changes in the resistance of the
vaginal mucus are shown by the  value of units
on a given day of heat. The best time for mating is indicated
 when you have a decrease in mucus resistance values.
12 to 24 hrs after peak is reached is the time for mating.
 
 

Which ever group/breed you own,
regardless of  breed the Draminski works
to help you with your breeding program !