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   (rightly or not) attributed to the sire, so your dog's reputation is
   at stake with each litter he sires. You should be reasonably confident
   that the proposed breeding will result in good puppies.
   
   If the owner of the bitch is a novice, are you prepared to assist with
   advice on whelping and puppy care? These people will expect you to
   have the answers. Sometimes entire litters of puppies are dumped on
   the stud dog owner when the bitch's owners can no longer cope with
   them because they didn't realize what a responsibility caring for a
   litter involved. Are you ready to take care of and place your dog's
   offspring if this should happen to you?
   
   Are you prepared to deal with cases where you are certain your dog is
   not the sire of the puppies but the bitch's owner insists that he is?
   Or if the owner of the bitch insists that you must have allowed a
   mismating to occur when she was boarded with you? Disputes of this
   sort can become very ugly very quickly.
     _________________________________________________________________
                                      
Genetics

   _If a purebred dog of breed X mated with a purebred dog of breed Y,
   both meeting health standards for their breed, is there a better
   chance the offspring would be healthier than a same breed mating
   because the gene pool is larger?_
   
     In terms of health alone the first answer would be that in breeding
     two healthy dogs it shouldn't matter if they're the same of
     different breeds, you're apt to get healthy pups. But this doesn't
     take into account the question of recessives. Suppose you breed two
     dogs of different breeds that both have the same incidence of a
     recessive health problem. The pups would have the same odds of
     having that health problem as purebred pups of either breed. On the
     other hand, suppose the two dogs were of breeds that have no
     recessive health problems in common. This would reduce or eliminate
     the odds of the puppies of having the health problems of either
     breed. This is the classic explanation for the theory of first
     generation hybrid vigor. The resulting pups should not be bred
     though, since they'd have a good chance of having the recessives
     from BOTH breeds, so the grandpups would be inclined to be worse
     off than the purebred offspring of their grandparents. An excellent
     set of articles dealing with "hybrid vigor" can be found in
     _DogWorld_, Jan 1997 by George Padgett DVM. Another _very_
     important point to keep in mind is that when a purebred carrying a
     genetic defect is crossed with another breed or mixed breed, the
     "bad" genes do NOT "go away" even though they may not be expressed
     in the offspring. If crossed with another dog carrying the same
     defect, the offspring of that breeding _will_ demonstrate the
     defect.
     
   _Purebred dogs have all these diseases, though! It seems that you
   never hear about mixed breed dogs with problems._
   
     Responsible breeders try to identify genetic diseases their dogs
     might be carrying and to eliminate them by careful breeding. It is
     ironic, though not surprising, that their efforts to identify and
     weed out genetic problems have lead some to cry "look at all the
     genetic diseases purebred dogs have!" A moment's careful thought
     will lead you to the conclusion that mixed breeds carry the _same_
     harmful genes (their parents, or their parents' parents, _were_
     purebreds, after all). The differences are
     * with some recessive disorders (though not _all_ genetic defects)
       the disease is less likely to be _expressed_ (though it can still
       be inherited by offspring)
     * you have lesser likelihood of ever identifying or eliminating any
       harmful genes your mixed breed may be carrying
       
     Also, if you stop and think about it, many mixed breeds are simply
     not tested for most problems. When they get older and limp, it's
     just considered old age, although it could well be hip dysplasia.
     When they get older and start to go blind, it could be PRA, but the
     owners are unlikely to test for this. It's not that owners of mixed
     breeds are bad, by any means, but they are not looking for possible
     inheritable problems, either.
     
   _When you breed two different breeds together, what kind of variation
   can you expect?_
   
     Pfaffenberger's book has some interesting data on this. He did some
     experiments with four different breeds. They were dogs of
     approximately the same size, but very different physical appearance
     AND behavior. The results he saw in the first and in subsequent
     mixed generations are pretty interesting.
     
     Let's look at a common crossbreeding: "cockapoos" (which are _not_
     purebred dogs, nor registered with any registry). These are crosses
     between Cocker Spaniels and Minature or Toy Poodles. The dogs
     actually vary quite a bit, some being more poodle like than others,
     and some being more cocker like than others. However, they are
     generally all a small sized, buff colored shaggy dog. If you breed
     two cockapoos together (not generally done), you get an even wider
     variation of dogs -- some look like Minature Poodles, others like
     Cocker Spaniels. The reason for this is the recessive genes hidden
     in the first cross that came out in the second generation. This is
     actually a visual example of why "hybrid vigor" doesn't hold.
     
   _What is outcrossing?_
   
     Outcrossing is where the sire and dam are totally unrelated,
     preferably for three or four generations. The true form of an
     outcross is between two entirely different breeds because in
     reality the members of most registered breeds come from a common
     ancestor (althought it may be many, many generations back). It is
     very rare for outcrossed puppies to be uniform in appearance.
     Usually there are a very large ranges of sizes, coats, colors,
     markings, and other distinctive characteristics. Outcrossed litters
     are generally heterozygous, and do not reliably reproduce
     themselves, so even the nicest puppy in the litter may not later
     produce the best puppies.
     
     Outcrossing is generally used to introduce something new to a line
     -- a better head, better colors, better front, etc. Usually the
     puppies retained from these breedings are bred back into the
     breeder's original line to standardize them back into the line's
     general characteristics and reproducibility -- with the one desired
     characteristic. The tricky part is that other characteristics may
     come along for the ride!
     
     If you are dedicated enough, you can eventually continue breeding
     by outcrossing alone (but don't expect instant or quick results).
     You should pick dogs that complement eachother well and are similar
     in general appearance. This is a long hard road to eventually
     developing a line. Through outcrossing, many health problems can
     quickly be eliminated (or just as quickly added into your
     breeding), but usually you do sacrifice some show quality and
     producibility.
     
     You have to remember that dogs that appear totally healthy may be
     carriers of genetic problems. To find this out, test mating is done
     to a dog that is affected with the genetic problem (resulting
     usually in puppies that are both affected and non-affected
     carriers) or by inbreeding to a related dog that also doesn't show
     the signs of being affected (usually littermates are used) this
     will usually result in some puppies free of the problem, some
     puppies as carriers, and some puppies affected if both dogs carry
     the problem gene (this is not as accurate as breeding to an
     affected dog, but you are less likely to have to put all the
     puppies down).
     
     There are variations on outcrossing. A "true" outcross could be a
     dog that has totally unrelated dogs bred together throughout the
     pedigree. This is very rare. On the other hand, "linecrossing" is a
     form of outcrossing where dogs from unrelated lines are bred to
     produce a new line. The sire and dam are usually very linebred from
     their prospective lines and the resulting puppies are varied in
     appreance, some looking like the sire's line and some looking like
     the dam's line and some looking like mixtures of both lines.
     
   _How about line breeding?_
   
     Line breeding is when the sire and the dam are distantly related:
     e.g., grandsire to granddaughter, granddam to grandson, second
     cousins, half cousins, uncle to niece, aunt to nephew..... The
     general strategy is that there is a common ancestor that is being
     doubled up on both sides. So the desired dog appears several times
     in the pedigree.
     
     This is probably the most common strategy in breeding purebred dogs
     (and in developing new breeds, for that matter). Though this
     method, new genes are slowly introduced and unwanted genes are
     slowly replaced. The actual rate varies by how strongly you line
     breed. It sacrifices little overall quality in terms of show
     quality. Usually the puppies are rather close in general
     conformation. The only problem with this method is that it often
     takes several generations to get poor genes out, (or adding desired
     genes in) resulting in many puppies that have the same genetic
     problems (or virtues) that their parents have. And then because
     some breeders are more interested in winning, they do not place the
     affected puppies on spay/neuter contracts. This is both a blessing
     and a curse for the breed. If the breeder is very careful, affected
     pups can be used wisely to prevent loss of quality, but still
     remove the affected genes by only breeding the affected pups to
     known non-carrier relatives. This way the breeder can again try to
     "edit out" the bad genes. It takes longer this way but less show
     quality is lost in the process. This process results in dogs that
     will often reproduce their same level of quality. This is refered
     to as reaching homozygous litters (more genes of the same kind
     apparent in the puppies).
     
     Inbreeding and linebreeding really differ only in degree.
     Linebreeding is less likely to cause harm than inbreeding.
     Inbreeding is not for novices. Knowledge of genetics and the breed
     is required for success. For good results it must be well-planned
     and breeders must be ready for whatever problems it presents.
     
   _And inbreeding?_
   
     Inbreeding is where the sire and the dam are closely related:
     mother to son, father to daughter, sister to brother, half sister
     to half brother, cousin to cousin. People disgree about the exact
     point at which inbreeding becomes linebreeding. Inbreeding is the
     quickest way to find out what poor genes are in the line and what
     dominant characteristics are in the line.
     
     Although many people are disgusted with the idea of this family
     incest, it is an extremely useful tool for diagnosing what genes
     are present. If the genes for bad eyes are present, but hidden or
     resessive, this will bring them out to their full extent. If there
     isn't any bad genes, then the puppies will be of very close
     uniformity and very able to reproduce themselves (theroretically).
     This is a homozygous breeding. The resulting puppies will have a
     lot of genetic material that is the same as their parents and
     grandparents and will be close genetically to each other.
     
     Inbreeding doesn't introduce new genes and does not eliminate bad
     genes that the line already has. It only shifts them around like a
     rubix cube. This often results in litters with high show potential,
     if the quality was high to begin with. It shows you what recessives
     you have lurking in the dogs' backgrounds -- _both_ good and bad.
     But there are drawbacks. Besides the possibility of bad recessives,
     inbreeding exclusively will eventually lead to infertility. It's
     like a xerox machine. After so many copies, you have to renew the
     ink. The same with dogs, you have to introduce new genes. No
     reputable breeder will use inbreeding exclusively, and many
     breeders simply never use it. Usually, you will only find: very
     experienced breeders, ignorant breeders, and puppy mills making use
     of this technique.
     
     Inbreeding increases the chance that a gene obtained from the sire
     will match one obtained from the dam, both stemming from the common
     ancestor(s) on which the individual was inbred. Thus, inbreeding
     tends to make animals homozygous rather than heterozygous. The
     inbreeding coefficient measures the resulting increase in
     homozygousity. All breeds have a given degree of homozygosity the
     mating of two dogs from the same breed would not produce a
     recognizable specimen of the breed!
     
     Inbreeding increases homozygosity and decrease heterozygosity. So
     it can duplicate both desirable and harmful alleles, both of which
     can be unsuspected in the line, and may appear. Inbreeding does NOT
     create anomalies, it brings present anomalies to the surface. Even
     when the anomalies are present, inbreeding might not reveal them.
     However, once revealed, then the breeder can do something about
     them in the next generations of breeding.
     
     An increase in harmful recessives is undesirable but it is not a
     major drawback if they are identified early. The effect of
     inbreeding on major polygenic traits is greater. Generally, traits
     that are highly inherited (ie largely additively controlled) are
     not adversely affected by inbreeding but, traits under non-additive
     control, especially those tied to dominance and thus not of high
     heritability, are often markedly harmed by inbreeding.
     
   _OK, how do pedigrees figure into this?_
   
     Remember that it is difficult to spot unaffected carriers. When an
     affected dog shows up, its pedigree is often examined for likely
     carriers. For example, PRA is a common problem in many breeds.
     There are dogs that come down with PRA that have a certain ancestor
     in common. That ancestor may then be considered a possible carrier
     and line breeding on him is avoided. This is a simplistic picture,
     obviously, since it's possible for an unaffected non-carrier of PRA
     to come from an unaffected carrier that came from an affected dog
     (therefore the affected dog is in the unaffected dog's pedigree).
     If a general blood test is ever developed that shows the presence
     of the recessive in an unaffected dog, then much more accurate
     breedings may be done; currently this is only possible for Irish
     Setters.
     
     There is rarely only a single problem a breeder is trying to screen
     for. Suppose a suspected carrier of PRA is known for producing
     excellent hips. A breeder might therefore introduce that bloodline
     into theirs for the hips, and be willing to have the possibility of
     PRA show up in the line. In screening out one problem you might
     have to accept the possibility of another appearing.
     
     Examining the pedigrees also lets you know what percent of ancestry
     the dogs share (since the relationships are often much more complex
     than simply cousins or aunt/uncle, the degree of common ancestry is
     often given as a percentage instead) and decide whether or not it's
     acceptable given your current goals.
     
   _What are like-to-like matings and compensatory matings?_
   
     Like to like mating implies the best to the best and the worst to
     the worst where the worst is not used at all. For most breeders,
     like to like matings are between dogs which resemble each other
     greatly and so similar type dogs are bred. These dogs may or may
     not be closely related.
     
     The pups resemble their parents because of the genes in common with
     them. If those parents resembled each other their progeny would be
     even more like their parents. This tends to make the population
     look more uniform, however there is little increase in prepotency
     from this technique.
     
     Compensatory Mating: This unlike to unlike mating is used by
     breeders to correct for a defect in an animal by mating it to
     another animal that might correct for the defect. The system is
     basically simple but the breeder must identify faults and virtues
     and it requires breed knowledge. The pedigrees of both dogs should
     be examined carfully to try to identify the ways in which the dogs
     differ and what the expected outcomes could be. A correct dog and
     not one who errs in the opposite direction is required. That is, if
     you want to improve structure, look for a dog with correct
     structure and not an overbuilt dog. This technique often results in
     only one or two pups with the combination desired.
     
   _But this is all very vague and complicated!_
   
     Yes, it is. There are no easy answers, and there are different
     things to consider in every breed. This uncertainty with respect to
     genetic inheritance is exactly the reason that breeding is so
     difficult to do right. It helps immensely to have a "mentor",
     someone who is familiar not only with the breeds, but the lines
     your dog belongs to -- advice from such a knowledgeable person is
     often extremely valuable.
     
     If we knew everything about genetics, we wouldn't _have_ problems
     with our dogs any more. We'd eliminate Hip Dysplasia, PRA, heart
     problems, thyroid problems, seizures, etc. within a few generations
     if we knew everything. Unfortunately it's an art that few people
     are actually very good at.
     
     _________________________________________________________________
                                      
References

   "So you want to use your Dog At Stud?" From the Literary Spot, the
   newsletter of the Central MD Dalmation Club 12/89 via Retriever
   Believer, the newsletter of the Labrador Retriever Club of Southern
   California 8/91.
   
   Tucker, Kathy. "Why are you Breeding?", printed in various
   newsletters.
   
   Whitney, Leon E (DVM). _How to Breed Dogs_ 384 pg. Many case studies
   on breeds, breed crosses for dominance studies, Myths and fallacies
   about breeding dogs, inheritance of traits (such as temperament,
   health, intelligence, and abilities).
   
   Wilcox, Bonnie (DVM). "Things to Think about Before Breeding Your
   Dog." DVM, printed in various newsletters.
   
   Willis, Malcolm B. _Practical Genetics for Dog Breeders_. Howell,
   1992. 228 pgs with appendix for calculations -- several graphs,
   charts, and pictures.
   
   Willis, Malcolm B. _Genetics of the Dog_. 417 pgs with breed specific
   information on many breeds -- plus several charts and graphs.
     _________________________________________________________________
                                      
   
    Breeding Your Dog FAQ
    Cindy Tittle Moore, rpd-info@netcom.com
    
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