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. |