Puppies Litters (Large vs Small) and The Effect Litter Size Has on Adult Dog Size

Discussion in 'Labrador breeding & genetics' started by RyanRJ, Mar 2, 2019.

  1. RyanRJ

    RyanRJ Registered Users

    Oct 21, 2018
    I had an interesting conversation with a few colleagues at work today regarding canine litter size. Now, none of the people involved with this conversation appeared to have any expertise in breeding dogs/dog biology. However, their lack of knowledge in this area did not stop strong opinions from forming, again, despite none of them presenting facts to back up their claims.

    The conversation had to do with the approximate size of adult dogs, and the cause and effect relationship to how adult dog sizes are impacted by the number of puppies birthed to small, versus large litters…or so the argument went.

    Just to entertain my curiosity, as the conversation itself was interesting and thought-provoking, I figured I would post the question here to see what opinions/facts you all can provide. So here it goes…

    Regarding puppy litters, does the litter size (the number of puppies birthed) affect the size of the puppy, or how big the dogs will be as adults?

    For example, take two puppy litters where the sire and dam from each litter are equal (or close to being equal) in weight and height respectively. In this example, one litter produces 4 puppies and the other litter produces 13 puppies. Does the disproportionality in litter size, 4 versus 13 puppies, affect the overall size of the puppies birthed when they reach adulthood? Without other mitigating factors, and only taking into account litter size, is it probable the dogs from the litter that produced 13 puppies will be smaller on average in their adult life, than the adult dogs from the litter that produced 4 puppies?

    This is Labrador related because I'm expecting to adopt another labrador soon, and this is what started the conversation, as this is the scenario that played out with the breeders I have looked at.

    From my perspective, I could care either way, the size of the dog is irrelevant. My last labrador Olive was a small girl at 50 pounds, and she was one of the best dogs I could have asked for.

    I don't think litter size affects the size of dogs when they reach adulthood, but, this is just my opinion. I'm interested to see what others know about this topic.
  2. Ski-Patroller

    Ski-Patroller Cooper, Terminally Cute Forum Supporter

    Feb 8, 2016
    Portland, Oregon & Mt Hood Oregon
    I'm no expert, but Lab litters are often large. 10-12 pups is common. From what I have seen the size of the pups is not much of a predictor of the size they will grow too. Cooper was a tiny pup, and grew up to be quite large 75#, 24". The size of the parents is the best predictor.
  3. Plum's mum

    Plum's mum Registered Users

    Jan 1, 2017
    East Sussex
    My girl is from a litter of 7, she was the same size as all her siblings when I chose her but very slight now, just 20kgs (44lbs) at 2.5 years old. Most people who meet her think she’s still a pup.
    I don’t know the sizes of the rest of the litter, however.
    Cath likes this.
  4. Aisling Labs

    Aisling Labs Registered Users

    Jan 6, 2018
    Genetics determine the size of the puppy at maturity.

    The largest in a litter is not necessarily the largest at maturity, it was simply a more food motivated puppy who got a lot of the food and probably had a better position in the womb allowing it to have a higher birth weight than others.

    Small litters, where the Dam has a great supply of milk, are usually larger (not necessarily at birth but as they feed and grow) than a litter with 9 puppies in it. Once the puppies are weaned the lighter ones begin to catch up to the heavier ones because the fight for a nipple is over. (8 Nipples - 9 or 10 puppies...8 nipples - 4 or 5 puppies....you get the picture.)

    It is genetics AND spaying or neutering before the pup is at full weight and height which affect the size of the adult labrador.
  5. Kami Kern

    Kami Kern Registered Users

    Sep 7, 2017
    Central Illinois
    No. The puppies in the 4 litter will be slightly bigger at birth but they would mature to about the same size as their parents. So litter size does not affect individuals mature sizes that's my opinion anyway!

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