Question about litter size

[Lord Goliath]

I've been wondering about litter size.  Have you noticed that certain bitches seem to have consistent litter sizes? Also have you noticed if there is any  effect that could be attributed to stud/bitch combinations?  For example if you breed stud A to bitch B is there a tendency to have different litter sizes than with stud B and bitch B?

Thanks in advance.

[Lovabullwrinkles]

James, in my experience, litter size seems to be determined more by the female.  We used different studs with Lola's 2 litters and she had 8 puppies each time.  We did have semen analysis done with both studs prior to insemination, and 1 male had significantly higher counts that the other.  Apparently, that didn't make a difference because Lola seems to produce a lot of eggs.

With the breeder we got Dora and Bessie from, her females tend to be pretty consistent also.  She bred Dora's mom and dad together for 3 litters, and she had litter sizes of 10, 11, and 6 (Dora's litter was the smallest because the mother got an infection and only Dora and her brother survived).  Dora's maternal grandmother has been bred to different studs over the years and has consistently thrown litters averaging between 7-10 puppies.  Most of the females owned by Dora's breeder produce upwards of 7-10 puppies a litter.  She has been developing her bloodlines for 20 years, so there seems to be a genetic component to litter size as well.

I know with Rita's last 2 litters out of Mazey (Hefner's mom), she used the same stud (Warrior) and had litter sizes of 7 and (I think) 4.  That was a back-to-back breeding, though, which might explain why Mazey produced fewer eggs.  She also did 2 breedings of her female Pebbles with Graham, and those litters produced 3 and 2 puppies respectively.  Again, it seems like some females produce a lot of eggs and some only a few.

I am by no means as experienced as some of the other breeders on the forum, but I thought I would throw my 2 cents in. 

[Lord Goliath]

Thanks Jodi. It sounds like, from your experience anyway, that litter size is more closely linked to the bitch than to the  bitch/stud combination.

Anyone else want to weigh in?

[RainbowRita]

I agree with Jodi. Generally speaking, if there are enough sperm to fertilize one egg, there's enough to fertilize them all. By the way, Mazey's first litter was five puppies. So she was 5, 7, 4. All puppies survived.

All of these litters were conceived with only one breeding each time with shipped in "chilled semen" via a surgical AI "implant" procedure. So with those kinds of breedings, timing is very crucial. If the surgical implant is done too late, the eggs will be dead before the sperm arrive, too soon, and they won't be ripe enough for fertilization. There is approximately a three day window to get the eggs fertilized once the eggs are ripe. So progesterone testing is a must, as is an experienced staff to interpret the "numbers" accurately. If the timing isn't optimum, you will see smaller litter sizes as fewer eggs might get fertilized than were actually produced.

I attended a breeding seminar where a reproductive specialist veterinarian said something interesting. She said that litter sizes tend to be smaller from many "show lines" of dogs (not just Bulldogs) than from "backyard breeders" or puppy mills. That's because BYBs and mills are selecting primarily for large litter sizes because the more puppies that survive, the more profit from each litter. Appearance is not as important as most people just look at how cute the puppies are, not what they will look like as adults.

Show breeders on the other hand are selecting for other factors, and are focusing more comformation and temperament than higher fertility rates. If anything, we tend to go the opposite direction and try to breed a bitch that has difficulty conceiving just because we admire her for other reasons. However, if we ignore these reproductive issues we can expect to see more of them over time.

[Lord Goliath]

Great info.  Thanks Rita and Jodi.