I've seen two bucks fighting as late as January 2nd (and they were both 150+"), so I don't think there would be any reason why rattling couldn't work later in the season. However, I do think the bucks attitudes are a little different later in the season as they get run down and less ambitious. Not much different than most hunters do in regards to hunting after the rut as they get burned out from many sits. Remember, what we call "the rut" is really only the week or two period in the fall when the highest percentage of does come into estrous. The number of does in estrous looks like a bell curve. Some can be very early and some can be very late, but the percent chance that they will be in heat is greatest at what we call "the rut". This could be as low or lower than 40% of the does and fawns that will come into heat during this time.