# Breeding question: litter size determined by sire?



## GottaLuvMutts (Jun 1, 2009)

Just out of curiosity...I have no intention of putting the answer to any use:

I friend of mine recently bred her male golden (who was from a litter of 11) to two bitches on the same day. Both bitches gave birth within the last 2 days to litters of 10 and 8! The sire was passing out cigars :wink:

A somewhat reliable source informs me that this is rather a lot of pups for a golden to produce, but that litter size tends to be genetically determined and is more dependent on the sire's litter size than the dam's. 

First, is this accurate? And second, can anyone provide a biological explanation for this? I'm trying to wrap my brain around how this could work, but I'm not having a lot of success.


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## RaeganW (Jul 14, 2009)

The only explanation I can think of is maybe the viability of the sperm is more important than the number of eggs? I don't know exactly how it works in dogs, but if a bitch had say 10 eggs released but only 5 sperm were strong enough to get up there you'd only get five puppies. So the bitch is still the limiting factor, but the stud determines what percentage turn into puppies?

Congratulations to your friend, there was a Golden litter here this winter that had 15!


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## BradA1878 (Nov 28, 2009)

Masha and Luytiy were mated twice, one litter produced 9 puppies and the other produced 4 puppies. Same sire each time.


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## Willowy (Dec 10, 2007)

But males release like millions of sperm every time, don't they? I don't see how anything other than the number of eggs the female drops would determine litter size. 

Actually this came up on the cat forum. Someone (someone not too reliable) mentioned that some cat breeders will "half-neuter" a tom (remove one testicle) so that he'll make smaller litters, supposedly. The general consensus is that that's an old superstition, since a male can make plenty of sperm with one testicle.


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## GottaLuvMutts (Jun 1, 2009)

Willowy said:


> But males release like millions of sperm every time, don't they? I don't see how anything other than the number of eggs the female drops would determine litter size.


My thoughts exactly. Twins run in human families, but it's dependent only on mom's family history, not dad's.


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## lil_fuzzy (Aug 16, 2010)

As in humans, it's the amount of eggs produced that determine how many babies they have.


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## Willowy (Dec 10, 2007)

Do Goldens typically have smaller litters? In Labs, 8 would be a smallish litter. 10-12 would be average. More than 12 would be large. Willow came from a litter of 13.


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## ChaosIsAWeim (Feb 12, 2011)

Well not neccisarily, it is a little of both. The amount can really only be determined by how many eggs are dropped. But how many get fertilized is determined by how good the dogs sperm is at swimming. That is why lots of people I know have the dog collected to determine if the dog has good swimmers.

To my limited knowledge on goldens, the do actually have nice sized litters double dogits is not unheard of like it is in other breeds. But breeds can surprise you, my oldest bulldog is out of a litter of 9, and she had two litters of 4, but her daighter had 6, the sire of the daughter's litter was a singleton.


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## Elana55 (Jan 7, 2008)

Lot of goldens in my Dog Club.. and many very large litters (9 plus puppies). Goldens and labs are known for large litters. 

That being said, I know of a GSD who had 9 puppies and 10 puppies (Atka's Mother actually). Different sires.

With cats, ovulation is stimulated by barbs on the Tom Cat's penis. He actually tears her on his way out and that action stimulates ovulation. In cats it is the number of matings at the right time that _may_ increase litter size. If more than one Tom mates with the Queen, you can get kittens sired by both.


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## tirluc (Aug 29, 2006)

the # of pups is determined by the bitch.....and, kinda as a rule of thumb, a bitch in her young yrs (2-6 span as they shouldn't have pups b/4 and i feel any older is too old) will have generally the same # as the litter size they came from, maybe 1 above or below.....Tir came from a litter of 7 and had 7 in her 1st litter and 6 in her 2nd......if they are bred beyond their prime, they tend to have smaller litters.....


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## Spicy1_VV (Jun 1, 2007)

Yes to a degree, though I've never noticed a correlation between his litter size. It has to do with sperm count and viability. Yes they have millions but think about why. Many will die and their are also different types of sperm with different jobs. Humans produce millions of sperm even though their is only 1 egg to fertilized (usually) and only a single sperm is needed.

I know two brothers, healthy dogs, young but one has a low sperm count. He was bred to a female and it resulted in no pups even though it "should have" if all up to her.

I agree some of what's been said.
A female limits the max number of the litter. Only 2 eggs you will only get 2 pups.
However 15 eggs doesn't mean all will get fertilized, you could only have 10 or 12 pups. 

Then there is timing too. The sperm come into play there if bred early the sperm will arrive before the eggs are ready to be fertilized. Which means many will probably die. The more sperm a male produces the better. 

Females male also re-absorb a zygote or some may fail ti implant meaning less pups born.

Another thing is y chromosome sperm swim faster but also die faster, while x swim slower but live longer. This could effect litter size depending on the timing and the abundance of x vs y the male has.

It's true older dogs may not be as fertile but I don't see much change when they are just beyond their prime and the healthier the dog in the older years also seems to effect fertility. 

My 7yr old had 6 which is a little small but my 4yr old had the same. Same sire.


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## GottaLuvMutts (Jun 1, 2009)

Ok, starting to make a little more sense. I don't know the ages of either of the bitches, but the sire is ~2.5yo.

The thing about x and y chromosome sperm is the same in humans. It has to do with the weight of two x chromosomes vs. a y and an x.


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