I DON'T RUN MINE AFTER THE 14TH DAY OF BEEN IN SEASON,BUT LIKE SOMEONE SAID ON A SIMILAR THREAD ABOUT BITCHES BEEN IN SEASON IT DEPENDS ON THE INDIVIDUAL BITCH EVERY BITCH IS DIFFERENT,WHAT I FIND IS THROUGH THE HORMONAL CHANGE THE ABDOMINAL MUSCLES AND INNER STOMACH MUSCLES RELAX IN OTHER WORDS NATURES WAY OF PREPAIRING THE BODY FOR CONCEPTION THEN BIRTH,SO FOR A RUNNING DOG THIS COULD EFFECT PERFORMANCE ANYTIME WITHIN THE SEASON/HEAT AND THEN UPTO 4 TO 6 WEEKS AFTER DEPENDING ON THE INDIVIDUAL ANIMAL,HENCE THE WORD 'HITTING A FLAT SPOT'BUT ALOT OF RABBITING PEOPLE MIGHT NOT SEE THE DIFFERENC