Size Genetics

[Prydenjoy]

I've heard that if you outbreed you'll often end up with pups bigger than both of the parents, but wouldn't it be the case that you're just as likely to get pups smaller than both of the parents? And others that are somewhere in between? Is it risky business outcrossing with a dog on the upper limit of the standard? Or even a dog whose parent was on the upper limit of the standard?

[Lowenhart]

I've heard that if you outbreed you'll often end up with pups bigger than both of the parents, but wouldn't it be the case that you're just as likely to get pups smaller than both of the parents? And others that are somewhere in between? Is it risky business outcrossing with a dog on the upper limit of the standard? Or even a dog whose parent was on the upper limit of the standard?

It's not as simple as "all outcrosses produce larger". Complete outcrosses (such as mixing breeds) regularly produces offspring bigger than both parents. This is one sign of "hybrid vigor" (though they are not true hybrids). In purebreeds, outcrosses are rarely true outcrosses. Most share some genetic history if you trace back far enough.

Some dogs are prepotent for attributes, some will produce their own size 9/10 when bred to any size male and others are not strong for producing their size.

Looking at the complete pedigree and having an idea of the size of siblings etc can give you an idea of what size you will get but there are no guarantees. It takes many years to come up with theories and only 1 litter to smash them.

What you have to decide is what attributes you want from the litter, you can't have every. If the dog you wish to use is on the tall end and you end up with tall/oversize progeny you may have to not show that generation and find the size in the next generation.

I have successfully used oversized dogs to get small offspring. Lots of good luck on my part but I am very conscious of the size behind my dogs.

On the right is an oversize male who was very very nice, in the middle is his daughter. To the left is the granddaughter/daughter (it is 3 generations) and she is just within standard at the bottom end.

We then bred the same import to the middle bitch and the end bitch (mother and daughter). The mother produced 2 oversized dogs, the daughter produced only small to medium sized offspring. These breedings were for all intents "outcrosses". The import however had loads of oversized dogs in his pedigree despite being standard size.

[Prydenjoy]

Thanks heaps for that. I suppose (theoretically at least) if I wait until Mango is fully matured, if she is light, small and dainty then it would probably be less risky to breed her to a larger dog (I'm assuming the size genetics I studied at uni probably have some relevance to dogs as well). Because my breeding plan does not allow me to have too many dogs at home (I'm not set up for it) I would probably go backwards from what you said, perfecting the small and dainty, then adding in a larger dog with other qualities that I like and hope for something in the middle. In the meantime that dog may have some promising offspring that share his desirable qualities but are a little bit smaller than he is. I don't particularly want to skip a generation and not show it as I only have one bitch of my own that I am showing now!

Ah so much to think about, I was up half the night thinking of my "breeding plan" and little Mango is not even a year old yet

Beautiful dogs by the way, especially the bottom one!

[angelsun]

There are dogs out there in every breed that are called "size reducers" and "size increasers". Regardless of their pedigree, they consistantly bring size down or bump it up, depending on what is needed, no matter what they are bred to.

I've known in my breed, a size reducer, that although he was a top end dog, never produced that size and in fact, had a problem producing large enough to make standard size! These dogs are very valuable as when used properly (and not focusing on whether they are linebreeding to the breeders pedigree, or outcrossing) they do their job and it is the next generation (their offspring) that the breeders begin to consider pedigree more closely.

there are many wivestales out there when breeding dogs, such as if you breed a large/oversize one to a small/undersize one, you'll get the in the middle size...sorry....you get big ones and little ones mostly and unfortunately if the bitch is the small one, you might get a section during whelping too!

I have some size in my pedigree that I am aware of. Because the standard for my breed here is an inch shorter than I was used to working with in Canada, I have to be VERY careful of this in the future. No longer will I be able to have my 20" (50cm) dogs, because the size is now 45cm here. After years of consistantly having boys this size, I've got to find a structurally sound size reducer, and hope that when I cross back into my own lines, I can maintain this size.

This is what makes breeding interesting, because as much as I know I can succeed, I know that I will breed some biggies. The trick with me then, is to know how to spot them when young, and remove them from my future breeding plans by finding them great pet homes.

[Prydenjoy]

Thanks angelsun. I'm considering running on all of the suitable pups until 6 months of age or so to get an estimate of size before choosing one to keep. But then I have to consider that the homes they go to wont get them as a puppy and that will be quite unfortunate in itself. I know that sometimes a bigger pup is not necessarily the biggest as an adult. Seeing as bitches are usually smaller than dogs I'm thinking that if I keep a bitch from the litter, and if the litter turns out quite large she should still be within the standard and I can breed her to a size reducer in the next generation. First and foremost I want to be breeding healthy pups with a good temperament, and I'll work on the finer details such as size as I go along.