Line Breeding is the process whereby relatives are bred to one another in a breeding process.
Many species line breed naturally. Many don't due to the sheer number of available mates. Humans play a role in the line breeding of many species.
When you line breed, you specifically plan to "set" characteristics in the progeny. Sometimes the breeding does not go to plan, and the characteristics you wanted the progeny to inherit do not come through, while some previously recessive (or hidden) characteristics can come out.
You know what you are getting (mostly).
It gives you the opportunity to "set" desired characteristics in your lines which you hope will be easier to replicate in future generations
Sometimes it does "set" some characteristics in your lines that you don't want. These then are usually very hard to lose.
Sometimes it doesn't work, and none of the progeny are worth carrying on with. In such case, the progeny are best spayed/neutered and placed in pet homes.
One of the interesting outcomes of line breeding is that you can get to see if your dogs carry a health problem that you did not know about. This means that you can then plan better in the subsequent litters. However, on the other hand, you may be left with a litter of pups with a severe health problem. The key is to be honest to yourself about the health problems in your lines. Then you can work to get rid of them. It is pointless to put your head in the sand and try to ignore your health problems.
Please note: every single breeder has health problems/risks in their lines.
When we outcross, we take two completely unrelated lines and breed them together. This is what I call "Jackpot mating". The chances of getting something good out of such a breeding are remote. However, if the breeder is planning ahead, this may merely be a step in a longer term strategy. For outcrossing to work, the next logical step is to breed close again to the line.
When you outcross you basically leave it up to great randomness about what the babies will look like. You will NOT get the best charactertics of the mother and the father. In all likelihood, you will get a very average looking litter or worse.
In order to outcross successfully, you have to understand that within every breed there are different types. For example, in boxers there are great differences between the US type and the English type boxer. To outcross a US and a UK boxer together, you are unlikely to have a very good result. However, if you outcross a UK with an Italian type boxer, you will probably get better results all other things being equal.
So, when you outcross, please be sure you understand type, and that you have chosen which type you prefer. If you decide to bridge the gap between types, than that is a step which will probably take you the better part of 10 years to gain the success you are striving for.
One of the fallacies of cross breeding is that the genetic diversity you get will give you a better pup. This is completely unfounded in any scientific study. What you do get, is a lot of "unknowns".
Example: A breeder is developing what she calls are her "lines". Let's call her lines "Boomerang". She really likes a dog call "Figjam" from another set of lines. The figjam lines have nothing in common for at least 10 generations. To breed a Boomerang bitch with a Figjam dog would be called an "outcross". It is unlikely that the progeny out of such a breeding would be anything great. However, if the progeny was put back to either a Boomerang or Figjam animal, then the progeny from that mating would in all likelihood be better. The breeder than achieves the aim of getting Figjam into her lines, while maintaining her own lines.
Any decision to breed a species should occur after a lot of thought and research. It should not be something that is undertaken lightly.
These are the sorts of questions you need to consider:
-Are the dogs I want to line breed together of good quality? (this quality should be proven in the show ring)
-Do I have photos of the animals back several generations? (this will help you see which characteristics are carried)
-What will I do if the breeding is a disaster and none of the progeny has the characteristics I am looking for?
-Am I breeding to the most suitable dog for my lines, or the most popular one in the breed at the moment?
Furthermore, there are loads of "old-timers" in every breed that will be prepared to help you make these decisions. There are plenty of people around you that can and will help you as long as they can trust you with the information that they give you.
If you are new to dog breeding and are looking for a mentor, you may want to join the dog mentor email list, where such assistance can be found.
In-breeding is when you breed very, very closely. eg: brother-sister breedings.
The fundamental question you need to ask yourself before every breeding is - why am I doing this, and what do I hope to achieve?
I would love to be able to give you a definitive answer to this question, but really, the answer will come to you after considerable thought and research. Breeding is not an easy undertaking, and comes with considerable responsibilities. I think long and hard before I make such decisions. Right now, I am undertaking a strategic move where I'm going to an outcross - but which looks very similar to my breeding - and then will breed back along my lines. This is a decision based on the very tight lines I already have, a small gene pool, and a completely unsuitable gene pool from other local breeders.
Article submitted by: © Jane Johnson (Biography & Additional Information [1])
Links:
[1] http://www.petstyle.com/bios/index.aspx?id=231