Importing "Outside" Blood: For Better...Or Worse?
By Henning Lund Boxerhaven Boxers, Norway
On the SHOWBOXER-L recently, a list member suggested that importing boxers from another area of the world - especially from the countries in Europe where great emphasis is placed on working ability - would diversify the North American boxer gene pool in a positive way, and help eliminate some prevalent NA health problems. Another list member pointed out that just importing "outside" blood wouldnt be of any avail in solving health problems if we didnt make sure we were importing healthy blood from another countrys bloodlines; and that working ability did not necessarily ensure good health. As the owners of an American import and as breeders who have utilized the bloodlines of several different European countries in our own breeding program, wed like to expand upon those statements a bit.
First, in our part of the world, several "lines" live side by side, with very little exchange between them. Therefore, even within the small population of boxers we have in Norway and Sweden, there is a lot of potential genetic diversity that is not taken advantage of. If that is true in small countries like Norway and Sweden, it is probably also true in a huge country (huge in terms of both area and boxer population) like the United States.
Another point to consider: There is reason to believe that we don't have nearly as much BCM, for example, here as you have in North America. But BCM isnt the only health problem you have to watch out for. Importing new material is very useful and often necessay, but has to be done very carefully, and the risk is that you will import dogs that bring with them a higher frequency of other problems than you already have. Therefore, imports must be used with great care, and followed by careul screening and selection. (It isn't easy to be a good breeder.....)
There are two things (at least) to think about in this context. One is to import outside dogs to reduce the incidence of one concrete problem and to give you the chance to select from stock that is free from that disease. That is basically what breeders always have done with other traits. The other concern is a more abstract one, but probably more serious, and has to do with why we need to mantain a broad breeding base for its own sake.
When you linebreed or inbreed all the time, you will fix certain traits by making gene pairs homozygous. That is necessary in order to fix breed specific traits and also is a useful tool in establishing a line that you can say carries your mark. Inevitably, when you do this, you will also lose genes, since there is only limited room for genes in the chromosomes. You will get less genetic variation, and that in itself is a problem. I suspect that the biggest concern regarding inbreeding isn't the risk of doubling up on negative genes and getting some kind of unsuspected disease popping up. To some extent you can select against that.
There is, however, one system in the dog that is dependent upon as great a genetic diversity as possible, and that is the immune system. This system makes antibodies against all foreign things that enter the body, and each time a new "bug" shows up, new antibodies must be designed and manufactured. To be able to do that, there have to be many immune system genes available so that the organism (in this case, the boxer) can shuffle them around and try new combinations, and so make a new antibody that can take care of the new bug. There probably is very little opportunity to select for a good working immune system if this system hasn't got enough genes to work with in the first place. The immune system also plays an important role in fertility, the interplay between mother and foetuses, etc., so a good working immune system is of great importance.
In answer to the question of what diseases European boxers most often suffer/die from, you just cant generalize. Europe is a large and heterogenous area, with many countries, many boxer populations and many very different cultures. Of course, there are also different ways of thinking about boxers and boxer health. Boxers in Europe probably die from many of the same things as boxers in North America. In the UK, breeders have been concerned about SAS and have worked to reduce the incidence to a minimum in the boxer population there. The British Breed Councils control scheme has been so successful that boxers are no longer among the top ten breeds referred to the cardiologists, when just a few years ago the majority of referrals were boxers! In Scandinavia, skeletal problems have been a major concern for many years, and we have worked very hard to reduce the incidence of spondylosis in Norway and knee problems in Sweden. Now the attention has turned towards SAS here as well. In Germany detailed records have been kept, but generally about problems that can't be considered as health problems - like the numbers of white puppies and cryptorchids. They also keep records on Hip Dysplasia that show a significant improvement from 1968, when only 7.7 % of the boxers were free from HD and 25.8 % had "ubergangsform" (suspected HD, or "transistion state"), to 1980, with 30-40% of boxers free from HD and another 30-35 % affected. However, it seems that German breeders are now recognizing both spondylosis and SAS as problems in their population, and the new breed warden, Inge Gerwin, is obviously putting much energy into getting people to test for these things, too.
As for working ability and its relationship to health, I have to say, being European and living in a country where we have an influx of breeding material from (almost) all parts of the world, we have not experienced that dogs that come from "working" lines are any healthier or more long lived than other dogs. Look to another breed, the German Shepherd. That is a breed where, in general, much more emphasis is put on working ability than it is in boxers in most parts of the world, but they definitely aren't healthier than our dogs!
Another point in that context is that a boxer that is trained for working trials will usually have been able to achieve high merits by the age of, say, five. Many dogs, even if they have significant degrees of the more common boxer health problems, will last that long before they have to be retired because of those problems. Selection for working ability alone is not the same as selection for good health. Based on what we see here, there is no reason to conclude that European (Continental) boxers are healthier than other boxers.
So if you are trying to eliminate a specific health problem from your breeding stock, by all means take advantage of the genetic diversity available through "outside" bloodlines. But do not expect just any outside blood to be a cure in and of itself. You must be every bit as careful and selective (maybe more!) as if you were using a dog from another North American line.