Any stud dog should have his tubes cleaned out as you call it every month or two if not in use. I don't know about one day prior but if 2 or more I would collect him once before usage.
Just for the record, I collected 5 year old virgin male, to see if he was viable, for a possible sale to another country. His sperm was all but jumping off the slide. I was quite surprised. Each dog is different.
Yes I must admit I can never quite get my head around "cleaning the pipes" so to speak. I have never done it and when I know the boy is going to be collected to be frozen I don't do anything, every time he is collected he has sperm to spare very fertile are the words my vet used. Never done it and never will why waste the goods.
It's an old adolescent boy's wishful tale, translated into dogs. I'm wondering - if you do it to the dog and he enjoys it, is that bestiality? Would hate to get caught by the HSUS doing with my stud dog.