interesting breeding question.

[Narmowen]

1. Yep. Definitely genetics, IMO. Faith had 2 litters-7 & 6. Her daughter had 5. Her granddaughter had 3, 2 & 7. Her sister had 5. Faith's dam had 7 also.

Another line runs 3/4 every litter.

2. No, I believe it's also genetics. The male line determines if they produces males or females.

 

[granite]

Emma came from a litter of 8 puppies; and her litters were 6, 9, and 9. She's now retired and is focusing her mommy energies on squeaky toys. She is now obsessed with them (and licking the couch for some reason).

Sasha came from a litter of 4; her litters were 3 and 4.

The daddy-o of our house, Figaro, came from a litter of 5.

 

[Justicemom]

Keep in mind that bitches don't ovulate all at once - that's part of why one does multiple breedings. She may release one egg, then two a day later, then one more a day after that.

Actually they do ovulate all the eggs at once over a 24 hour period, about 2 days after the LH surge. LH surge is very brief and hard to measure in a laboratory so we use progesterone levels instead to help us know when ovulation occurs. The LH surge happens when the progesterone is about 2ng/ml.

Multiple breeding are done because we don't always know when ovulation occurs especially if we are just using days of estrus and even vaginal smears. We can get pretty close with progesterone levels(4-10ng/ml on ovulation day). Sperm can live up to 7 days after breeding in the female reproductive tract. But fertilization occurs about 2-4 days after ovulation regardless of the day of breeding and whelping occurs with great regularity between 62-64 days post ovulation. Note this is not breeding days. That is the reason for the 58-63 days whelping window when using breeding dates.

So if something is happening with the sex ratio then it has to do with type of sperm (x or Y) left in the tract when the eggs are ready to be fertilized. Also if you needed to only one breeding, the best chance for the best litter size for that bitch on that breeding cycle would be 2 days after ovulation.

 

[JessicaR]

Genetics do play some part in litter size, but I recently read a study on 1500 dogs(usually it's 500 for a study) that feeding Eukanuba performance blend produced on average 2 puppies more per litter. Not sure if this is just because it is a premium food or what the other food was that was being fed.

thats interesting. The womon I got Belle from switched her pomeranians to Eukanuba. She said since then she has had more pups, better weights, better coats and no deaths. I dont know what she was feeding before.

 

[tofu pup]

Actually they do ovulate all the eggs at once over a 24 hour period, about 2 days after the LH surge. LH surge is very brief and hard to measure in a laboratory so we use progesterone levels instead to help us know when ovulation occurs. The LH surge happens when the progesterone is about 2ng/ml.

Multiple breeding are done because we don't always know when ovulation occurs especially if we are just using days of estrus and even vaginal smears. We can get pretty close with progesterone levels(4-10ng/ml on ovulation day). Sperm can live up to 7 days after breeding in the female reproductive tract. But fertilization occurs about 2-4 days after ovulation regardless of the day of breeding and whelping occurs with great regularity between 62-64 days post ovulation. Note this is not breeding days. That is the reason for the 58-63 days whelping window when using breeding dates.

So if something is happening with the sex ratio then it has to do with type of sperm (x or Y) left in the tract when the eggs are ready to be fertilized. Also if you needed to only one breeding, the best chance for the best litter size for that bitch on that breeding cycle would be 2 days after ovulation.

Hey, thank you for that!

I'd always been told that they ovulate on successive days, meaning that some puppies could have been conceived a few days apart (meaning that, once they're born, you can have puppies that have a few days of gestational age between them). Old wives' tales abound!

 

[JessicaR]

I know in rabbits you have to be carefull about mating because you can have kits born premature if you mate them for more than 1 day. Usually the premies dont make it. But then rabbits, like cats are induced ovulators. I knew dogs were not induced ovulators, but I had also heard that they ovulate on successive days.

 

[danisgoat]

On litter sizes, I think it also has to do with how the breedings were timed... if you do only one breeding, or a series of breedings too early (when only one or two eggs are available) or too late (after most of the eggs have "gone by"), you end up with a very small litter.

I agree with this.

Our Shasta had 9 puppies one litter and 11 puppies the next litter.
Her son Cedar sired a litter of 9 puppies
Sassy (Cedar's daughter - one of the 9) had 3 puppies

We believe that her litter was so small because she was bred towards the "end" when most of the eggs went by. My mom took her to a male that was from Georgia but was field trialing in Ohio. By the time they got there, they may have missed that "window" by a day.

 

[seashel]

I know in rabbits you have to be carefull about mating because you can have kits born premature if you mate them for more than 1 day. Usually the premies dont make it. But then rabbits, like cats are induced ovulators. I knew dogs were not induced ovulators, but I had also heard that they ovulate on successive days.

This is interesting, I don't think I've ever had an early litter and I always try to get two matings. They ovulate in response to stimulation from a male. They (and Hares too) can also retain fertilised eggs in 'limbo' while developing an earlier brood, literally running two pregnancies together. Once I had this happen when one I had mated and thought had missed, produced a normal singleton baby 45 days later (gestation is usually 31 days). I know for certain she was not mated again.

Sorry for the diversion!

This is a fascinating thread BTW

 

[JessicaR]

This is interesting, I don't think I've ever had an early litter and I always try to get two matings. They ovulate in response to stimulation from a male. They (and Hares too) can also retain fertilised eggs in 'limbo' while developing an earlier brood, literally running two pregnancies together. Once I had this happen when one I had mated and thought had missed, produced a normal singleton baby 45 days later (gestation is usually 31 days). I know for certain she was not mated again.

Sorry for the diversion!

This is a fascinating thread BTW

Thats interesting, I have not bred a litter of bunnies in years, I am just now getting back into rabbits with my lionheads. I was always told breed them 1 hour apart and do a test mating on day 8 to see if she took. Must be another one of those wives tales.

 

[seashel]

Thats interesting, I have not bred a litter of bunnies in years, I am just now getting back into rabbits with my lionheads. I was always told breed them 1 hour apart and do a test mating on day 8 to see if she took. Must be another one of those wives tales.

I've always found the girls will let you know when they're ready - they won't leat the buck near if not. I mate twice on alternate days. Good luck with your lionheads. They are very cute rabbits. I breed Himalayan Netherland Dwafs BTW.