If you don’t know the basic principles of linebreeding, or what it implies, start up here in this section. If you know all that stuff and want to get to the good part, start here.
One of the most common pieces of advice given to new and experienced dog breeders is to linebreed their dogs. The reason this advice – which is about 150 years old and is a holdover from the livestock breeding strategies of the Industrial Revolution – has survived is that linebreeding, over time, creates a situation where your breedings will be more predictable.
Imagine that you are pulling from a giant jar of M&Ms. The jar is opaque; what you have grabbed will not be seen until you’ve pulled your hand out. You HATE the green ones and you’re not too fond of light brown. You really want the red ones and you’re neutral about yellow. Your first handful brings up a whole bunch of reds, some yellows, a few light browns, and one green.
From here you have a choice – you can either go back in for your next handful, or you can put the handful you already pulled out into a second jar. That second one is a magic jar, and it’ll instantly fill up with thousands of M&Ms, but they’ll be in the exact proportion of colors that you put in.
This is not a trick question – OBVIOUSLY, to get closer to what you want, you choose the second jar. Once the second jar fills, almost every handful you pull out will be pleasing to you. Sometimes, by accident of chance, you’ll get a lot of greens and light browns, but on the whole you’ve created a great way to get the M&Ms you want.
This is exactly the way it works in dogs. By starting with something you like, and then creating many more dogs closely related to the thing you like, you are stacking the odds in your favor.
The things that are very important to you – heaviness of bone, pretty head, or fill in a hundred other traits – will be statistically more likely to appear in a linebreeding, and over time this will lead to the creation of a “Line.” We all talk about “line” to mean a pedigree, which is fine and works in a pinch, but the truest definition of a line of dogs is a group of dogs related over multiple generations that is incredibly similar and predictable.
This point – where you have the happy M&M jar – is usually where the explanation stops. Of COURSE every breeder would want to do this, and so OF COURSE it’s the best way to breed.
However, what is not communicated – often because it’s misunderstood, because those passing along the advice don’t really understand it and are just passing along advice THEY heard, and back it goes for generations of breeders – is that the M&Ms are not coming by themselves.
Picture that each M&M is attached to a string of invisible mardi gras beads. You have fifteen small pieces of candy in your hand, and dripping between your fingers are fifteen yards of beads. That means when you put your handful of M&Ms in the new jar, you’re not just putting candy in – in fact, most of the jar is not going to be candy. It’ll be a big tangle of mardi gras beads with some candy attached to it.
Those invisible mardi gras beads are all the things that make up the invisible dog under the dog that you see and touch. They are the immune system, the emotional response system, circulatory, nervous, lymph, muscle development, bone growth rates, hormonal secretion, digestive… it goes on and on. And, of course, when you make your M&M color more alike, and more to your liking, you’re also making the bead strings more alike.
But – and here’s where the problem comes – you can’t see those beads when you’re making your choice between jar one and jar two. So NOW which one do you choose?
But – but – you say “Linebreeding concentrates virtues and flushes out faults!” That’s what we’ve heard, often from breeders advocating not just a moderate amount of linebreeding but of tightening and tightening as you go. You don’t just stick with jar two; you put a few M&Ms, just exactly the colors you like, from jar two into jar three. And from jar three you pick not just the colors you like (because now they’ll all be the colors you like) but the roundest and plumpest candies. Jar four, therefore, is all the right color AND very likely to be just the type of candy shell and just the consistency of chocolate you like. This is all GREAT, say the advocates of line breedings. And the very tightest of linebreedings is the best of all, because you have “concentrated virtues and flushed out faults.”
“Flush out faults” is a great example of people using words that sound good but are a disaster in real life. Flushing out genetic faults means making faults appear. So you have, for example, sister mom with no immune disorder, brother dad with no immune disorder, breed them together and you get three puppies with an immune disorder. This reveals (flushes out) an inheritable genetic disease in their familial lineage.
When breeders had no ability to outsource any kind of knowledge – in other words, 150 years ago – this could be useful. You’d then know that the family carried a inheritable immune disorder and you could stop breeding them, or breed them only to families whose breeders had done similar inbreedings and found that their families did not have that disorder. This practice was honed on cows, so the default answer was “eat them all.” You eat your failures, which are going to be the vast majority of your breedings.
Here’s the big problem nowadays: Now you have three puppies with an immune disorder.
This is where the whole strategy breaks down, when it comes to dog breeding. Nobody is (or should be) keeping entire litters to adulthood, and nobody is killing puppies anymore. You can’t make the problems you create disappear into the freezer. Those puppies go into pet homes and show homes, months and years before any of the “flushing out” is going to take place. In effect, you’ve given your pet homes the result of an experiment to see what bad stuff is in a family.
And this is where we, as breeders, have to stare this in the face. Is it ethical to try to make disorders appear, when we intend to put those disorders in homes?
I’m going to leave you with that – and look for some wise remarks in the comments.