Just a pondering to get everyone's thoughts - I know with humans they recomend 6 weeks inbetween if a man is donating sperm - what do you suppose the appropriate 'rest time' would be for a male ?
In order that you get the best sperm you can at each mating - how long should you wait? Are we talking hours ? Or a whole day?

This might help you work it out.

http://www.fertilitycommunity.com/fertility/how-does-frequent-ejaculation-affect-sperm-production.html

Human, not canine.   But I would think timescales might be simiar ;-)

When anyone has left a bitch with me, I always allow a daily mating if they are both up for it.  However, I don't leave them together (they would be at it all the time.)

I have never allowed my lad to serve 2 bitches close together.  Yet I do know of one exhibitor who has 2 bitches staying at the same time, and being served by the same dog.

Actually dogs are really designed to mate for about a week and then not for a longer period.

A canine fertility article I read ages ago suggested for collection collecting daily for several days (something like a week) and then resting for a few days.

Here we go: http://www.labbies.com/reproduction4.htm

Quality of the semen, therefore, is often more affected by factors other than age including degree of arousal, frequency of ejaculation, collection technique and sample handling. Since frequent ejaculation (daily collection of semen for 5 to 7 days) can cause a reduction in sperm output, studs in high demand may experience less than optimal fertility at certain times throughout their reproductive years. For this reason, it is recommended that sperm from valuable studs be collected and cryopreserved in sufficient quantities early in the male's career to ensure future availability. To this end, collection of semen on an "every other day" basis typically allows time for replenishment of sperm reserves........

Sperm are stored in the extragonadal compartments of the epididymis and the ductus deferens. The amount of reserved sperm will depend on the frequency and interludes between ejaculations. Total sperm counts in a sexually rested male encompass sperm reserves plus daily sperm produced by the testes. Sperm reserves are reportedly depleted by once per day ejaculation for 5 to 7 days. Therefore, once reserves are depleted, total sperm number will be represented only by the daily production of sperm by the testes.

I remember reading a discussion on CD regarding temporary problems with sperm loss, owing to high temperatures in summer, or high temperature due to illness  With the loss of sperm being noted about 6-8 weeks later.

Am I dreaming this? 

Difficult to find old posts these days, I can't even find old posts that I made.

It's very interesting - just wondered as some people tend to mate their dogs a few times each day when goog to the stud whilst others rest the dog for a good few hors/ days

As a non-breeder, my immediate thought would be to leave at least a week or two between matings in case any infections were passed on? To give symptoms time to show?? Is there any sexually transmitted diseases in dogs?

Yes dogs can get STI's, there is another post on here about the herpies vaccine :) weirdly there is a problem in Australia with the koala and chlamydia.

Would this be a further reason to leave time between matings? For example, if there were two closely planned matings between two different bitches, one of the bitches had 'X', the male mated her, caught it but before either of them showed symptoms, he had already mated another bitch and then the three of them had it?

I suppose this would only be relevant if the particular STI *could* be symptomless. Sorry to hijack the thread.. this needs a whole separate thread!

We fortunately do not have Canine Brucellosis in this country, so only the usual sorts of bugs can be passed during mating.

When I used a male in the USA he had been tested for this before being used again.

Canine herpes Vaccine is not a sexually transmitted disease as such as most dogs have ben exposed to it at some point via contact with others.

It only causes and issue if it flares up when a bitch is pregnant, due I assume to suppression fo the immune system.