INBREEDING,
LINEBREEDING
AND
OUTCROSSING


These days, with the enormous increase in those who wish to become breeders, there sadly seems to be a severe lack of knowledge as to just what it takes to become a responsible breeder. Many unfortunately, think it's just a matter of finding two individuals with working reproductive organs! Happily though, there does seem to be some public awareness of the significance of genetic diversity in certain individuals and the obvious advantage of breeding animals who are closely, or somewhat closely, related. At least within those who have sought to educate themselves on the matter.
In some respects, Genetic diversity might be considered advantageous in the total pool of domesticated horses but linebreeding and inbreeding can also have desired effects. The total gene pool (genetic diversity) for horses is extremely large. This is apparent when one considers all of the various breeds, crossbreeds and numbers therein. However, when this obviously limits the gene pool for that particular breed. The outcome of this, restricts all animals of that breed, to have a certain "look" and background. In earlier years of a given breed, animals who possessed the desired traits, were bred very closely to relatives who also possessed those traits - hence the beginning of the different "breeds" as we know them today. So let's have a look at just what Inbreeding, Linebreeding and Outcrossing are all about. Of course there is much more to it that that which I outline here, but it should give the newcomer to breeding, a little idea of just what it's all about.
First however, let us dispell some myths and legends about breeding. Responsible inbreeding or linebreeding, does not produce, midgets, animals with three legs, temperament problems, infertility etc. Outcrossing does not produce animals with no genetic problems or healthier, stronger animals! Hybrid Vigor is a myth. You can find just as many major problems in Outcrossed animals as you can in Inbred or Linebred animals. The key to ALL breeding, is to know what you are doing before you begin. Learn as much as possible about the breed, study the Standard of the breed, research all you can about animals appearing in the pedigrees of those you intend to breed, honestly evaluate their strong and weak points and don't breed with your "heart"! Just because you have a dog or horse you love dearly, does not mean he or she is of quality to bring into the world, the next generation of his or her breed. The larger percentage of animals alive today, have many genetic and other problems, which if bred, only produce more and more with the same problems. There are only two types of breeders. The irresponsible and the responsible. I'll leave it up to anyone reading this as to which their conscience determines they wish to be.


INBREEDING is a very close cross between a given pair of animals. This might be a son to mother, father to daughter, brother to sister, although that is not a common union. Inbreeding should only be attempted by extremely knowledgeable breeders who are most thoroughly aquainted with all the animals close-up in the pedigree, have a sound knowledge of those individuals as it applies to their health, longevity, quality, temperament etc. Certainly, well bred individuals from these types of close breeding, have been produced.


LINEBREEDING is the breeding of two animals who are closely related to the same ancestor or a couple of ancestors, but are little if at all, related to each other through any other ancestors. In a Linebred pedigree, a single horse and his ancestors might appear two or more times.


OUTCROSSING is the breeding of two unrelated animals - at least say within the first 5 generations. If one were to study pedigrees, it is almost inevitable to always to find many of the same horses appearing in the pedigree of both sire and dam, but for now we will consider an Outcross, the breeding of two horses which don't show the same horse appearing in the last 4 or 5 generations.


The purpose of both linebreeding and inbreeding is to bring improvement more rapidly and narrow the pedigree to a few closely related lines of descent. It reduces variability. It more quickly sets a "type" in your stock. It also brings out more strongly good and bad qualities including genetic problems which might have lain hidden before. It is easier to predict the result of a breeding by linebreeding or inbreeding, than the results of a complete outcross. If the selection of the ancestors or ancestor the sire and dam have in common, is an excellent example of the breed, then it would come as no surprise that the offspring would probably be superior. Judicious linebreedings have shown, in all breeds of animals, a real improvement in offspring. Remember however, this only comes about if the ancester chosen on whom to linebreed, is himself a particularly superior example of the breed and has shown through his offspring, that he does in fact reproduce himself reliably. The quickest and most certain way to produce superior offspring is by careful linebreeding. When considering linebreeding however, one must not consider the animal on pedigree alone. Much research should be done as to his possible weak points, his temperament, any genetic health problems he might have possessed, if he died young - what was the reason etc. With so many genetic problems within our animals today, it certainly is necessary to do as much research as possible on a given animal, whether he be living or dead. A horse bred on pedigree alone, without much knowledge of the horses therein - especially one who appears many times over in that pedigree, quite well might display many previously unknown genetic problems. This might be a propensity toward certain Cancers, Allergies, heart problems and more.
Close breedings certainly will bring out such ailments in offspring. It does not "cause" them, but instead displays them which obviously then allows the breeder to know just what he has in his line. Close breedings not only bring out the good and desirable traits, but those which might have been lying hidden for generations. Inbreeding and linebreeding therefore bring out in the open, the best and sometimes worst traits, in an individual. It is again the reason why it is so important to research as much as possible about a certain Stallion for example, to whom you are breeding your related Mare. There is no doubt, that all animals, have some imperfections and it is up to one's own desires, knowledge of the breed, knowledge of genetics and certainly one's conscience, just what faults one is willing to overlook in an otherwise spectacular example of a given animal. It is always unwise though, to double up on a fault. If your Mare has a particular fault which is not correct and you find objectionable, then it should be obvious that you wouldn't breed her to a Stallion with a similar fault. In fact, she should be bred to one who is excellent where she is faulty - if indeed she is breed-worthy at all.
Offspring of two unrelated horses, cannot be reliably predicted. They might resemble the Sire, the Dam or neither. If however, the product of an outcross shows him or herself to be of quality, it is prudent to bred them back into the strongest (most correct) line of their parents. So if one has set a certain type within a breed, which is now producing itself reliably, just when "does" one decide upon an outcross? Certainly with an outcross breeding you will lose a certain amount of that "type" which you have previously sought, but should you find that your heavily inbred or linebred foals are displaying some unwanted features, then it's probably time for an outcross - again though, only chosing supreme examples of the breed. Once again, using an outcross Stallion to your Mare/s, you would want to make sure you do very careful homework as to his background, what he has produced etc. Sometimes an outcross can bring a pleasant surprise and then one might consider breeding back into the line which the foal most displays. Always remember however, an outcross can sometimes bring the most unpleasant surprises and the breeder might lose what he has worked for in previous years, eliminating some of his ealier good qualities.
Regardless of whether you wish to Inbreed, Linebreed or Outcross, the main objective is to produce the best possible animal in the next generation. Without lots of research, homework, study, knowledge of the breed and it's Standard, you can never hope to produce that which you have in mind.


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