Genetic Health

Speaking Heresy; A Dispassionate View of Cross-breeding

By February 17, 2015July 5th, 2017No Comments


by C.A. Sharp

Several years ago the working Australian Shepherd community was rocked by a scandal. One breeder was alleged to have produced cross-bred Aussies/Border Collies and registered them as purebred Australian Shepherds, in order to give the pups produced an advantage in Australian Shepherd Club of America working trials.

An act of fraud may have been committed—on the registry and on the trial system, but ASCA could do nothing to prove the case and punish the perpetrator. By the time it became aware of the situation the parents of the alleged cross-breds were unavailable for blood typing. The club’s board subsequently set up a DNA parentage verification program, one of the first by a purebred dog registry, as a step toward guaranteeing the integrity of its records.

Fraudulent registration and cheating in competitive programs is unacceptable and should be punished whenever it can be proved. But this alleged fraud specifically involved cross-breeding. But is cross-breeding in and of itself an evil?

Pure breeds governed by closed registries are the norm in purebred dogs, but they are a recent phenomenon in domestic animal breeding. Existing registries were set up within the past couple centuries and few, if any, existed before that time. Prior to registries, pedigrees were not viewed as an essential part of breeding practice. Introduction of a totally unrelated animal wouldn’t be questioned, if it produced desirable offspring.

As European social thinking leaned toward theories of racial purity, these attitudes were extended to animal breeding. Registries were created so that the bloodlines would remain “pure.” The establishment of a reservoir of breed data—by way of pedigrees and whatever additional descriptive information was gathered—provided breeders with valuable reference material. Those knowledgeable in a breed could review a pedigree and have a good idea what lay behind an animal. Once sufficient dogs were enrolled, registries—and therefore breed gene pools–closed. Cross-breeding fell into disfavor as the resulting offspring would not be eligible for registration. Today, people attempting to create new breeds may find themselves accused of “mongrelization” by breeders and fanciers of the parent stock.

If a breed is numerous and descends from a large number of founders, sufficient genetic diversity may exist to keep the population healthy, so long as inbreeding isn’t heavily used as a breeding technique. But if a breed is small in numbers or, however populous, has experienced a genetic bottleneck the time may come when there is no place to go to breed away from genetic weaknesses. Even a breed as numerous as the Australian Shepherd provides examples of such genetic constrictions.

Aussies have three very distinct sub-populations, between which only minimal crossing occurs: The working lines, show lines and the Mini-Aussie, sometimes called the North American Shepherd. Dogs from of each of these sub-populations may be registered with the Australian Shepherd Club of America and might also be registered with other organizations, either as Australian Shepherds or, in the case of the Minis, as a separate breed.

The show dogs form the largest group and are mostly descended from dogs produced by the Flintridge kennel, which was active in the 1960s and 70s. The working lines are more varied in background but much fewer in number. The Minis, consist of dogs considered “undersized” by the standards of the breed as a whole; they are comparatively few in number and mostly descend from only three lines. The show-line Aussies and the Minis are experiencing difficulties with genetic defects. The problem is less acute in the working lines, due to their greater diversity, but may some day become so because they are so few in number.

Show-line breeders have the option of out-crossing to a working line, if they can find a working breeder who is willing to cooperate and if they can accept the fact that the practice is unlikely to produce instant show-ring success.

The Mini breeders are developing a separate breed, derived from but smaller than the Australian Shepherd. Small Aussies have always existed, but in a distinct minority. From some of these relatively few dogs, the minis were created. Recognizing that their gene pool was very restricted, the Miniature Australian Shepherd Club of America has formulated a plan to allow cross-breeding with Australian Shepherds. From their point of view, this is cross-breeding, because they consider their dogs to be a distinct breed. But they may cross only with Australian Shepherds, the original, larger, population from which they were derived.

Size criteria is an important aspect of breed type for minis, but they are also expected to look like Aussies. Mini breeders utilizing this program will select as mates Aussies that are themselves on the smaller end of the size range or which are known for consistently producing small offspring.. A special registration designation will be given to new animals admitted on the basis of size and to the offspring of cross-bred litters. The next generation will have its own code as part of their registration numbers. The following generation can attain the same registration status as dogs not resulting from cross-breeding or introduced individuals. These designations do not in any way penalize the dogs when it comes to competing in club-sponsored or sanctioned events.

The MCASA program is very new, so it remains to be seen to what extent breeders take advantage of it. But the program is well-designed with regard to their overall breeding goals and a concern for improving the breed’s genetic diversity.

Working Aussie breeders face the biggest challenge. The Border Collie cross-breeding scandal is so recent that most are ill-disposed toward the idea under any circumstances. But given their breeding goal—the preservation of the Aussie as a viable stock dog—they cannot readily turn to the rest of the breed for out-crosses. Herding behavior is genetically complex and dilutes rapidly if not deliberately maintained. While a fair number of show line Aussies might be able to pass a basic “herding instinct” type test, they do not have the drive and the highly-developed set of behaviors required in a true working situation.

The only viable source of fresh genetic material that includes working behaviors lies outside the breed, a source presently considered unthinkable and in any event not allowed by registry rules of ASCA or the American or Canadian Kennel Clubs.

But is cross-breeding really so unthinkable? Certainly, it is unworkable unless the registries allow it—as in MCASA’s program and those of a few other small registries and breed clubs (including the English Shepherd, another small-population herding breed.) But at some point, it may be the only alternative to genetic meltdown.

In other purebred species, some degree of cross-breeding is regular practice. The use of Thoroughbred crosses in racing Quarter Horse lines is an example. Cross-breeding has produced more than one new breed of market animal over the past few decades, in response to changing consumer demands and husbandry practices.

In dogs, closed registries and a ban on cross-breeding are the rule, but the rule is not universal even among the big, powerful registries. About fifteen years ago a researcher crossed a Pointer with a Dalmatian and then back-crossed to Dals in the subsequent generations. His goal was to eliminate inherited urinary problems that are present in almost every Dalmatian. In this he succeeded and the board of the breed club petitioned AKC to admit some of the products of this breeding program—dogs which had only that one Pointer in a five-generation pedigree otherwise full of Dalmatians. Two of the dogs were admitted, but the breed club’s membership raised a hue and cry, voting to rescind the request, so AKC refused registration to any more dogs.

The “cross-bred” Dals were free of the urinary problems. The membership of the breed club rejected them because they were often mismarks by their breed standard. A purely cosmetic problem that might have been corrected in subsequent generations triumphed over the elimination of a significant health problem.

Another cross-breeding effort which received registry sanction—this time from the Kennel Club, the English registry which is, if anything, more conservative than the AKC. Another scientist wanted to create Boxers which did not need to have their tails docked. So he cross-bred to a Corgi. (The bob-tail gene in Corgies does not produce the serious defects that sometimes occur in bob-tail Aussies.) After five generations he had Boxers that looked like Boxers and produced like Boxers but had naturally bobbed tails. Those dogs were allowed to be registered.

If a cross-breeding program were to be developed, it would have to be open and aboveboard, sanctioned and regulated by the registries. The people involved with both the above examples never made any secret of what they were doing and why. Under the right circumstances, even major dog registries can accept cross-breeding.

If such a scheme were to be workable in Aussies, in order to preserve working characteristics and/or improve overall health and genetic diversity in the breed, only breeds or individuals which exhibit an acceptable phenotype (the observable behavior, temperament and appearance) should be considered Where available, health screens should be required for recognized problems which exist in Aussies or in the other breed. DNA parentage verification should be employed to guarantee that the cross-breedings are as represented. Some process, as seen in MASCA’s program, needs to be in place to record the crosses and, over a set number of generations, accept them into full registration.

Finally, breeders need to be educated on what to expect. Cross-breeding is not to be approached lightly, nor should anyone attempting it expect a rapid pay-off. It is a breeding tool intended for long-term benefit. Considerable research will be required in order to make viable crosses. Does the other breed look and act sufficiently similar? Border Collies and English Shepherds are two breeds found in North America which might have something to offer. Other, breeds might be located farther afield—the Welsh Bobtail, German Coolie and Pyranean Shepherd come to mind.

No two breeds, however similar, are exactly alike. The Aussie breeder attempting to cross breed needs to know what atypical traits the cross-breeding is likely to introduce and how difficult they will be to select against in subsequent generations. For instance, if a coated breed is to be cross-bred with a slick-coated breed, all the resulting puppies will be slick-coated because the trait is dominant. However, since it is a single-gene trait, if only coated individual from the second generation back-cross are selected for further breeding, the atypical slick coat will be eliminated. But other traits will be more complex and may prove more difficult to weed out.

To be truly effective from a health stand-point, a number of cross-breedings over several generations would need to occur. The challenge would be to maintain the original type while doing it. Appearance traits can be recovered even in extreme cases, such as the Boxer/Corgi cross. But behavioral traits may prove harder to fix. These would require time, patience and careful study to determine what traits tend to persist and which can easily be bred away from.

Cross-breeding is not a panacea and is not something to be undertaken lightly or under anything but the most open and accountable conditions. But with some purebred gene pools shrinking and others riddled with genetic problems, perhaps it is time for dog breeders to give thought to that which has been considered heresy.

Copyright 2003 C. A. Sharp. All rights reserved. Australian Shepherd Genetics Institute