I always thought that the bitch was mated on days 11-14, counting day1 as the first day when red blood is seen. Reading some of the letters here it can be earlier! When is the best time? Can they mate whilst the discharge is still red? How often should they mate for success?

Welcome puddle---!
If you have been reading recent posts it seems any time between day 8 and 22
I think you have to trust the bitch & the stud to know for shure & you can mate every other day between these times if you wish?
it all depends on wether you think you have succesfull matting,size of litter you require Etc:

karl