When breeding? We only allow one tie per day and usually only two to three ties period. We count gestation from the day of the first tie since they generally take then. More than that is unnecessary risk and pretty pointless as they become infertile pretty quickly so no point in risking the serious injury that can result from a tie. There is more basic information for you on that process in the first link on that and I think I may have put it in another Q for you as well. :-)
q3388198.html
http://members.tripod.com/antique_fcr/goodbreeder.html
q3388198.html
http://members.tripod.com/antique_fcr/goodbreeder.html
