im interested to get your opinions on this :

we have several brood bitches and we used the same stud on them for a couple of years running. all the litters were fairly small, mostly 5's and 6's.
we then used a different stud for a couple of years in a row, and put over the same bitches, he has produced larger litters mostly 9's and 10's, the largest to date has been 15!!.

the first dog was linebred from good lines and very healthy.
the 2nd dog was also linebred from good lines, and again, very healthy.
both dogs came from large litters (neither were related to each other, or the bitches)
no changes were made to diet, worming treatments or anything else from the time we used the first dog, to when we used the second (and also, by the time we used the 2nd dog, the bitches were aged between 4 and 7 years old).

I was under the impression that fertility was a 50/50 thing, yet i read apost on here the other day where a man said that the size of the litter depends entirely on the amount of eggs released by the bitch. while I agree the bitch must produce the eggs in order for the dog to fertilise them, I also think the fertility of the dog plays a part!! as our breeding programme over the years has proven. this post has now vanished, so i cant recall who said this,(I think the mans name began with an A?) but I'm sure I cannot be the only person who feels that the size of the litter is dependant on BOTH parents, rather than the bitch alone. can someone (preferably who has experience of breeding for many years) please clarify whether the size of the litter can be influenced by the dog or not (from my experience, I believe the dog plays a significant part) thanks

Hi,
I personally don't believe that the sire (providing he is within the normal range for sperm production, motility etc) has any bearing on the litter size. As the sires you refer to were not related (to each other or the bitches - unusual), it could well be that the genes of the second were a better match than those of the first dog.

When my dog was young I had him sperm tested, purely because I wanted to use him on my bitch for her last time so it was imperative to know if his sperm was mature. He was apx 12months, he had, in the majority immature sperm, tail less etc. So yes if I had of used him she may well have missed or only had a couple of pups but within a couple of months I had him tested again and there were hundreds frantically swimming around in the 'one drop' but she would not of had hundreds of pups. So it is determined by how many eggs she releases and catching her at the correct time of ovulation. 

I would also say that is was mostly down to the bitch, an EX friend of mine breed her bitch to the same dog every season for 5 years :(,  the first litter she had 8, then for the next 3 litter's there were 7 puppies in each, the next 2 litter had 2 puppies in and the last one she had 7, so from this i would say it dose not have a lot to do with the dog as the stud was always in better condition then the bitch (as you can imagine)

Bitches produce eggs numbered in tens, dogs produce sperm in the thousands, so unless the dog is not producing healthy sperm the number in a litter depends on the number of  eggs available when the sperm is there to fertilize them, and that depends on the timing of the mating.

The condition of the sperm is laid down about 8 weeks before they are ejaculated so a dog that has been poorly or overheated may have a poor sperm count, and the same dog could have a much improved count at a later date and in a different test.

Does anyone know how long it takes once ejaculated for a dogs sperm to rejuvenate?

The links here and here seem quite helpful.
:)

Thank you :)

".. depends on the timing of the mating"

Could it be that one of the dogs used was more discriminating than the other? I had one boy who wouldn't try to mate a bitch unless his nose told him she was exactly spot on. Although he is experienced, his grandson will mate any bitch that stands. In this case it didn't make a difference to litter size, but I suppose in theory grandad might have produced bigger litters.

"the same dog could have a much improved count at a later date and in a different test"

Has anyone come across a dog with repeatedly good sperm tests that still can't impreganted a bitch? A boy I bred has been used six times (twice with the same bitch). Four of the bitches have had litters before or since he mated them, but he has never produced pups. He was sperm tested after his second failure and 2 weeks before each of his subsequent matings. He is in excellent condition, the timing has been good and there has been no problem with the matings.