Yes, as long as there are a few cows coming into their estrus cycle, the increased vocalization due to the rut will continue. Most cows come into their estrus cycle around the third week of SEP, but, those that don't "take" will have another cycle, even a third sometimes, until they take. Should you call during the early part of October? Absolutely. What calls should you use? It depends as all situations are different. You have to figure out what's occurring during a situation and go from there.........