Third week is definatly the best. Cows will be in esterous from opening week until well into rifle season. But the majority are in esterous the third week of september. Yes a cows is in heat for around a day , but all of the cows are staggered. Most will come in around the same week. Man would those bulls have a heck of a night if all of the cows were in heat the same night????? I have heard of yearling cows that will cycle around November and can be bred. The cows that did not take can also cycle again around this time. This rut is nowhere near the same as the september rut, but it does happen.