Can anyone tell me if once the female ovulates and is mated are all the eggs automatically fertilised? I did an earlier post about my girl( 2 matings 2 days apart from chosen stud then 2 days later accidental mating with friends stud),my question really is if she had ovulated around time of 2nd mating would there really be any eggs left to fertlise? thanks

Yes i heard this happen before half litter to one dog and other half to different dog so is a possiblity

A natural mating is nothing like in vitro fertilization.  

Fertilization doesn't happen straight away,  it can be days before the eggs are fertilized.   The bitch may be mated before ovulation occurs, and of course, then the eggs have to come into contact with the sperm, which can take some time too.

This is why there is often more than one mating, over a number of days, to give the best chance of success.

If, as you say, the bitch was mated by two different dogs, then she is likely to have a mixed litter

The only way to be sure which dog sired which pup is to DNA test both dogs, the mum and all the pups.

Yes you could easily have pups by both males. You will need to DNA profile both males and all the puppies so you can attribute each puppy to the correct sire before Kennel  Club registration can be undertaken. You need to complete specific forms for kennel club to submit samples

Yes im going to do that just to be sure.How long do the eggs live for?

In canines the eggs are shed over up to 48 hours and also live for about 3 days, after maturing (which is two days after ovulation).  so from first mature egg to the last ovulated one dying could be five days.  Male sperm can live easily a week and some bitches will mate some time before or during ovulation, so ample opportunities for several males to mate her and sire puppies.

You don't get different age puppies though as the dividing eggs reach a certain stage and then all implant together around 18 days, varying size and apparent difference in development is largely down to how crowded they are in their spot in the uterus and how good a placenta is developed.  many more eggs are fertilized than manage to implant and go to term.

Dill's reply is accurate.  

Perhaps, therefore, people can tell me why the Kennel Club, in it's 'wisdom' has sanctioned mating one bitch to two males (of the same breed!) DELIBERATELY.    It has been stated that this would widen a gene pool without the need for a bitch to have two litters from the same two different dogs.    Frankly, and I may be missing the point here, if I mated a visiting bitch to one of my stud dogs, and then discovered later that the same bitch had been taken to another male to be mated, and was, I'd go nuts.   And if I was told this was intended beforehand, I'd not allow the mating to my dog.   And further, if I discovered the bitch had been mated only days before to another dog, ditto - no using my stud dog!

In theory it might be a good idea for the bitch to only have one litter (and the intention is to DNA test the resulting puppies to know which dog sired which puppy), but I ask, what about the chances of infection - if the first male was carrying something infectious, and she was then mated within a short period of time, to another male, surely that would pass on infection?    For starters.

I wonder, realistically, how many times this will/has been done already?    Anybody know, or done this?

It widens the gene pool by effectively enabling a bitch to have two litters whilst in fact only having one, which is better for her welfare. DNA testing for parentage would make sure the right puppies were allocated to each sire. From what I've read it's fairly common practice in the US.

Oh common practice in the States eh.   There had to be a reason!!!

Interesting point. As it is also very common practice in the US to use AI rather than natural matings, is this why they don't worry about cross infections?

Deliberately mating a bitch to two different dogs would only be worthwhile in breeds that have large litters surely?

In our breed,  where the litter average is about 4 pups, then it would be pointless.   

I've also thought the risk of infection much greater for the bitch and for the dogs, after all, if more bitches are mating more dogs per season, then there's more risk of infection.   

Same as for humans, the more partners you have had, the more chance of pickiing up an std.

I would certainly consider the dual sire option, my breed has large litters and I choose to breed infrequently so when two potential sires have equal merit a dual sire litter would be great. In practice most stud owners would not agree due to concern about cross infection ( not really convinced this is a big issue TBH ) and AI is not that successful in UK so I guess it will be a rare event in UK for all but accidental matings

But if you have a dual sired litter then presumably then you would want to keep a pup from both sires. Keeping littermates whether or not they have different sires brings its own set of problems.

I suppose you'd still keep the best of the litter while hoping someone would want the best from the other sire to show....

But if you have a dual sired litter then presumably then you would want to keep a pup from both sires. Keeping littermates whether or not they have different sires brings its own set of problems.

Extremely good point! To me it would mean I would definitely not consider it.

I would assume that the owner of one of the sires in such an arrangement might want to have pick of the pups sired by his/her dogs.

No I would never keep two pups, I would hope sort the best pup from each litter and keep one and to place the other pup with someone who would compete and hopefully maximise its potential.

I was offered this when I went to the USA, but as the dogs were litter brothers (though quite different attributes) I went with just the one.

It is often suggested when one of the sires is by AI, so at least with a second natural mating, gives a higher chance of getting a litter by at least one.

Of course with using AI, whether one dog or more are used the issues over practicalities are ironed out.

Can you just imagine having to work out how the stud fees would be paid, (per puppy basis I assume, and how many stud owners would be happy with that?) travelling to owners of two males in possibly opposite ends of the country, deciding which would be used first, alternate days maybe LOL, logistic al nightmare.

Re risks of infection etc, street dogs don't form proper packs like wolves and bitches would mate while receptive to as many males as got the chance.

It does make some sense in large late maturing, but short lived breeds who have huge litters, like Great Danes for example, giving a bitch a chance of having more varied offspring.

I can't see how in modern small kennels it would be of much use as a breeder generally will not be looking to keep more than one puppy from a litter, so would need to be sure they can place pups from the other stud usefully, as otherwise it seems and awful lot of added trouble and expense..

Sorry wrote my reply but didn't post until after I'd walked my dogs, and so didn't see most of the other posts, which covered same ground.

Yes.  AI is used out in Canada/States regularly, especially with popular stud dogs, specifically to help avoiding the risk of infection.    When we took one of our bitches south, from Toronto, having travelled 12 hours down there, she was more than ready, he wasn't - and in the end she heaved a sigh, literally, and sat down, ignoring him.   We took them both to their vet the next morning - she was indeed ready, so we had an AI done so at least something was there, given the distance travelled!   We did get a half-hearted natural mating (slip) the next day.    Only 4 puppies however.

I'm still not convinced re allowing a mating from two separate dogs during the first season and I'd love to know how popular this has turned out to be!!!

As far as keeping more than one puppy from a litter - we have always run on at least two puppies from our litters - and they usually ended up 'sticking'.