The Math of Dog breeding
Most of us who breed dogs are not scientists. Some have medical degrees in nursing or
work in the veterinary medicine. But most can not explain exactly why mutations and faults
occur in dogs. You have to have a degree in science and have studied this particular field of
science before you can have a real clear understanding of genetics. Most of us need a
simpler way to make sure we don't cause problems for the dogs who are born in our homes.
The easiest thing to do is look at in terms of simple Math. Although it wont add up like math.
If your dog has a dominant genetic fault and you breed to another dog with the same
dominant genetic fault you are going to get 75% -100% of their progeny having this same
dominant fault. All the puppies will carry this fault in their genes as recessive if its not
dominant.
If your dog has a dominant genetic fault and you breed your dog to another dog with the
same but recessive genetic fault you are going to get 50% or better of your progeny who
have this same genetic fault with 75% or better of the progeny carrying this fault in their DNA
as recessive.
If you breed 2 dogs who carry a recessive genetic fault and its bred to another dog carrying
the same recessive genetic fault most likely you are going to get some puppies who will be
born with this genetic fault as dominant and some carrying it as recessive but it is not likely
that all puppies born will carry the fault . This is the nightmare of dog breeding. Because
recessive genetic faults can not be seen by just looking at your dog or even by having the
dog examined. There are tests that can be done to pinpoint some genetic faults in dogs but
most of us can not afford this type of testing and still sell a puppy at a reasonable cost.
These tests are not always as accurate as we would like them to be. We need to rely on the
honesty of the breeders we receive our dogs from. It is generous to say, honesty is a shaky
thing in the dog world
The one thing we all do have on our side is that all dominant genetic faults can be seen.
This is why all dogs used in your breeding program should be examined by a veterinarian
before being used for breeding. It is best to get a veterinarian who specializes in the faults
your breed is prone to. For the chihuahua it is problems with the knees and tendencies for
brain disease in puppies. They also have a tendency to hypoglycemia and I believe some
families have this to the point it is a serious problem. So these things must be cleared
before you decide to breed this dog.
There is no way to avoid recessive genetic faults entirely. Dogs that are used for breeding
should have a careful record of their line so we know what family they come from and the
problems this family has had. Stay away form closely line bred dogs as the chance of getting
two dogs carrying the same faults from these dogs is higher and thus passing these onto
their progeny in either dominant or recessive state.
Even if these simple and fairly inexpensive things are done by all dog breeders, the health of
dogs would start to improve instead of decline as we are watching it do.
As long as people breed any two dogs together (no matter what the reason) and as long as
there are people willing to buy from people who do this we are going to continue to find
these faults in our beloved dogs. Also, as long as there are people willing to risk genetic
deformities to get a certain look so as to make a name for themselves in the show dog world,
we are going to see more brand new genetic disease.
Us home pet dog breeders who make up a large percent of the dogs being born can do our
part by simply having our dogs examined by a veterinarian prior to adding him/her to our
breeding program. If a fault shows up in a breeding, do not repeat this breeding. These are
simple rules to follow and have been around for a long time. It always amazes me how few
people follow these simple rules to insure their puppies are healthy when born. While
always keeping standard in mind we should always put health and temperament first.
Mutations are a whole different story. When a dog has a mutation, such as the merle color
it can not be recessive. If you have a merle dog you will see it. It can not be solid black and
carry the merle mutation. I hope I understand this properly but mutations occur within the
DNA and are actually caused by something called an allele or a string of chromosomes
that change the message the DNA puts out to the cell. Certainly dwarfs are mutations and
certain color patterns are also. These mutations cause other things to go wrong with the
dog some more serious then others. I believe there is a lot more known about the color
mutations then about the dwarf mutations. So all I can offer is my own observations on
this. This is what I have observed thus far. It seems there has been an epidemic of tiny
dogs born because of the consumers demand and willingness to pay high prices for
these dogs. People breed tinier and tinier dogs together and seem to be concentrating
this mutation and causing very tiny dogs to be born. There is so little known about why
these dogs are so small that this is like walking through a cave with a birthday candle. You
just can not see the steps ahead of you well enough to not trip and fall.
I guess these tiny dogs are some kind of novelty to people or maybe its a fad. But the tiny
little dog is who is suffering. These tiny creatures are prisoners in their own bodies and
sometimes are prisoners in their world also because they are confined for their protection.
I feel so bad for a dog who is not allowed to be a dog. These are not toys but they have
desires just like any other living thing. Yes they are cute and their brave way of looking at
their world is an inspiration. But their lives consist of endless hours of boredom. I love
dogs. I love what dogs are meant to do. I love how they follow me around the house.
When I get up and leave a room all my dogs will get up and follow like my happiness is
their soul responsibility and they must be there for me. I find such happiness in taking my
dogs in the backyard and watching them sniff the ground looking for that special smell
that will just make their day. I love to watch them play their game of ,"I got the toy and now
you try to get it " as they chase each other around the room. It is not safe for any 2 pound
dog to do these things and thus it cheats him out of his birth right to act like a dog. Ive
now had 2 of these dogs. One lived only 7 months as she had a serious type of dwarfism
that is fatal. I have one now who must live in a guinea pig cage as regular dogs cages
have wire spaced to wide apart. He would crawl right out of them. I don't know if this little
guy is unhappy. He appears to be OK. But I know he will never be able to live the life a dog
is meant to live and this makes me feel sad.
I wish this madness would stop before it is to late. We don't know what troubles we can
cause for these dogs as we stumble around in the darkness of ignorance. With the
advances science makes, I can see a light at the end of the cave. But I have to wonder if
we are being to careless with this tiny dog breeding before we have all the educational
light necessary to make safe decisions.
I hope I am not misunderstood. I don't intentionally breed dogs to weigh under 3 pounds.
My smallest dog is a little guy named Snoopy who weighs only 3 & 1/2 pounds. It seems
Snoopy will throw these tiny dogs no matter what the size the mama dog is. My attempts to
breed him to 7 pound and larger dogs has not achieved my goal of getting something in
between. The recent study I read on why these dogs are small that came out in the year
2007, helps me to understand a little why this is so. You can read the information for
yourself on line by looking up the University of Utahs study on this in a press release article
entitled "Why Small Dogs Are Small." This study was conducted by 3 scientists and they
found some interesting things about our small dogs and their DNA. Their names are K
Gordon Lark, Lee Siegle, and Kevin Chase. If you put " Why dogs are small " in the search
bar of your search engine then you will come up with information on this. I am so glad
someone is finally taking the time to study this. As we learn more it will make breeding
these small dogs safer.
But if I understand the article correctly then it really does not matter who I breed Snoopy to,
he will always throw the small puppies because this is not an already known type of
mutation but something different and it effects the DNA in a different way. There have'nt
been any studies done on these dogs who weigh only ounces as yet . I hope someone
does in my lifetime and we can get a clearer picture.