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Dog crossbreed

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A pointer - dalmatian cross.

A dog hybrid (also called a designer dog) is a new term for an individual dog with ancestry in two different purebred dog breeds, traditionally called a crossbred dog. Designer dogs are described by whimsical portmanteau words, such as cockapoo. Dog hybrids (designer dogs) may be first generation crosses from two purebred breeds, or any of various backcrosses, or the result of breeding successive generations of crosses in an effort to create a new breed of purebred dog, or outcrosses of any of those; the term hybrid dog (designer dog) does not have a consistent meaning.

Definition of hybrid

File:Saarloos-Wolfhund.jpg
A wolfdog, or wolf-dog cross. Dogs descended from a type of wolf, and wolves and dogs are the same species, Canis lupus, though it was formerly believed that the cross was a hybridization of two different species.

In biology, the word hybrid has two meanings. The first meaning is the result of interbreeding between two animals (or plants) of different species, such as a mule (Equus caballus + Equus asinus) or in a cross between a lion and a tiger. Hybrids in this more common usage are often (although not always) sterile.[1]

Breeding within the same species, but from two distinct populations, is a secondary use of hybrid, but is not a correct term. This second meaning is most often used in plant breeding.[2] It is unknown how the term hybrid came to be fashionably used to refer to a crossbred dog, since all domestic dog breeds are all the same species, Canis lupus.

Dogs and wolves were once thought to be separate species, so a wolf-dog cross was called a canid hybrid (of the first type, under the information available at the time.) Today, it is recognized that wolves and dogs are of the same species, Canis lupus, and a wolf-dog cross is called a wolfdog.[3] Some fanciers cling to the older incorrect term, and still call wolf and dog crosses (and their descendants) wolf-dog hybrids.

Definition of crossbreed

A crossbreed or crossbred usually refers to an animal with purebred parents of two different breeds, varieties, or populations, usually deliberately bred for some purpose. A crossbred dog differs in this way from a mixed breed dog (also called random-bred or mutt) which has unknown or complex ancestry.

In crossbred dogs, because some traits are dominant, breeds tend to pass on some physical characteristics to crosses more than others. Border Collies and some Spaniels, for example, often produce offspring with similar coats and ears. The crossbred offspring of German Shepherds often have Shepherd faces and other characteristics. Crossbred dogs may vary in which characteristics of their purebred parents that they inherit, even in the same litter of puppies.

Designer Dogs

The Encyclopaedia Brittanica traces the term designer dog to the late 20th century, when breeders began to cross purebred poodles with other purebred breeds in order to obtain a dog with the poodles' hypoallergenic coat, along with various desirable characteristics from other breeds.[4]

The connotation of the term designer dog is that the breeding is by design, between a deliberately chosen sire and dam, as opposed to an accidental breeding. Some breeders have taken this a step further, breeding a specific crossbreed to others of the same cross, setting a standard, and documenting the ancestry of puppies so bred over generations, in order to create a new breed of dog.[5]

A Chihuahua and a Dachshund crossbreed, described with the portmanteau word Chihuachshund.

The primary identifying mark of a designer dog is that the resulting crossbred puppies are described with a portmanteau word made up of syllables (or sounds) from the breed names of the two purebred parents, such as schnoodle (Schnauzer and poodle cross).[4] Other purebred breeds are being crossed to provide designer dogs described with a wide range of whimsical labels, such as the Chihuachshund (Chihuahua and Dachshund cross), the Afador (Afghan Hound-Labrador Retriever cross), and even mixed breeds (with multiple breed ancestors) are being labeled in this manner, such as German Chusky (German Shepherd Dog, Husky, Chow Chow).[6]

Specific designer dog name labels are popular because some percentage of designer dogs with the same breed ancestry will look similar to each other, even though a crossbreeding does not result in as uniform a phenotype as the breeding of purebreds. The labels are useful to breeders in the marketing of puppies, and in the creation of affinity groups and clubs for owners of the designer dogs.

A Lakeland Terrier and a Patterdale Terrier crossbreed may be either a pet or a working terrier. Working dog crosses are not typically given portmanteau word names.

Another defining characteristic of designer dogs is that they are bred as companions and pets. Working and hunting dogs deliberately crossbred for a particular working purpose are most often referred to by a type (not breed) name, such as Eurohounds (racing sled dogs) or Lurchers (hunting dogs.)

Although designer dogs are often celebrated for their novelty, an underlying motive for crossbreeding is an attempt to reduce the incidence of certain hereditary problems found in the purebred breeds used for the cross, while retaining their more appealing traits. Jon Mooallem in the New York Times writes, "Given the roughly 350 inherited disorders littering the dog genome, crossing two purebreds and expanding their gene pools can be “a phenomenally good idea,” according to one canine geneticist — if it is done conscientiously."[7] But crossbreeding for a particular style of designer dog may not work out as intended; instead of the desirable traits, the resulting litter may have a combination of the undesirable traits of the two purebred breeds. Wally Conron, the originator of the Labradoodle (bred as a hypoallergenic guide dog from a carefully selected sire and dam) in 1989, noted that although the first Poodle-Labrador Retriever breeding produced a success, "our next litter of ten labradoodles produced only three allergy-free pups."[8]

Crossbreeding has not been well studied in dogs, although it has been for livestock. The heritability of the desired trait being bred for (such as a hypoallergenic coat) needs to be known; "Heritability is the proportion of the measurable difference observed between animals for a given trait that is due to genetics (and can be passed to the next generation)."[9] Without that knowledge, it is far less likely for a crossbreeding to consistently achieve an intended appearance or behaviour than it is for a purebred breeding. In addition, the goals of dog crossbreeding may be harder to define than the goals of livestock crossbreeding; good temperament may be harder to define and measure than high calf weight.

Designer dog breeders are often criticised for being more interested in profitable puppy production than in dog health and welfare. Wally Conron comments on the popularity of crosses after his introduction of the Labradoodle: "Were breeders bothering to check their sires and bitches for heredity faults, or were they simply caught up in delivering to hungry customers the next status symbol?"[8] Designer dog puppies sometimes bring higher prices than the purebreds from which they are bred,[10]. Finding a breeder who does health testing and considers hereditary compatibility of breeding stock is as important for a designer dog as it is for a purebred.

The fanciers of designer dogs respond with a reminder that all modern dog breeds were created from earlier breeds and types of dogs through the same kind of selective breeding that is used to create designer dogs. The Toy Poodle was bred down in size from larger poodles, most likely by crossing with various very small Bichon types, such as the Maltese and Havanese, although it occurred before the careful recordkeeping that is now done for modern purebred breeds.[11] Most of the modern breeds have ancestries that include various older dog types and breeds; see individual breed articles for details of the origin of each breed.

Health of crossbreed dogs depends on their being descended from healthy parents; breeders who select their breeding stock for cost-effectiveness and who skip health testing for the same reason will not produce puppies that are as reliably healthy as those bred by more conscientious breeders. However, studies of longevity in dogs have found some advantage for crossbreeds. "There was a significant correlation between body weight and longevity. Crossbreeds lived longer than average but several pure breeds lived longer than cross breeds, notably Jack Russell, miniature poodles and whippets"[12] Small designer dogs might also be expected to have very long lives, as they have both the advantages of small size and of crossbreeding, but that was not covered in the study. In general though, it is believed that crossbred dogs "have a far lower chance of exhibiting the disorders that are common with the parental breeds. Their genetic health will be substantially higher."[13]

Many breeders of designer dogs take advantage of the fact that people like a pet that is unique; "It’s human nature to aspire to own something a little different, a little fancy or in short supply."[14]

Genetics

Crossbreeding to take advantage of the increased chance that a recessive detrimental allele will only be inherited from one parent, and therefore not expressed in the phenotype of the offspring, is only one strategy breeders can use to decrease the incidences of genetic faults. For example, large dogs such as the German Shepherd Dog often suffer from hip dysplasia, a multi-gene trait strongly affected by environment. Mating a German Shepherd, a breed known to have about a 20% incidence of this disease (ref:OFA), with a dog of a different breed not known to suffer from hip dysplasia like the Greyhound, reduces the likelihood that the cross-breed produced will suffer from hip dysplasia. Mate the same German Shepherd to an Otterhound (dysplasia incidence about 52%) or to a small dog such as a Pug (62%) or a Norfolk Terrier (37%), and the outcome might be considerably different. Breeding dogs that have been tested free of dysplasia offers a similar result, with the added benefit of producing offspring that are less likely to carry the defect, unexpressed.

Knowing the disease incidence in the breed, and the genetic history of the individual, is ultimately important in dog breeding. Having the parental dogs genetically tested for defects known to be troublesome to their breed (or breeds, in the case of mixed parentage) will do as much, or more, than simply choosing dissimilar individuals with functional reproductive tracts. Genetic health must be approached from many angles. Some schemes are effective for the short-term, but disastrous in the long. Others are slow to take effect, but that effect is long-lasting.

Mating two different purebreds to decrease the likelihood of inheriting a particular genetic disease, without consideration of all the other physical and mental attributes that comprise a suitable pet and companion, is as likely to fail as any other single-trait selection scheme.

Registration and recognition

Dog crossbreds ("hybrids") are not recognized by any major breed registry, as crossbreeds are not one breed of dog, but two. If both parents are registered purebreds but of different breeds, it is still not possible to register a puppy as two different breeds.

If crossbreed dogs are bred together for some period of time, and their breeding is well documented, they may eventually be considered a new breed of dog by major kennel clubs (an example of a recent crossbreed becoming a breed recognised by all major kennel clubs is the Cesky Terrier) New breeds of dogs must have a breed club that will document the ancestry of any individual member of that breed from the original founding dogs of the breed; when the kennel club that the breed club wishes to join is satisfied that the dogs are purebred, they will accept and register the dogs of that breed. Each kennel club has individual rules about how to document a new breed. Some minor registries and internet registry businesses will register dogs as any breed the owner chooses with minimal or no documentation; some even allow the breeder or owner to make up a "breed name" for their pet.

Crossbred ("hybrid") dogs, created by breeding two purebred dogs of different breeds, have the advantage of heterosis, or hybrid vigor, and may be stronger and healthier than either of the parents. This advantage can be progressively diluted when two hybrids are bred in the attempt to create a breed. The best way to continue taking advantage of hybrid vigor is from the breeding of two different purebred breeds. [citation needed]

Affinity clubs and web boards provide social opportunities for owners of the variously-labeled crossbreed dogs and a place for breeders to advertise puppies. There are also many other specific Designer Dog dog fancy associations.

Portmanteau names

A 3 year old Labradoodle.

With the long-time popularity of the label cockapoo, used since at least 1960 and constructed by combining elements of its two contributing breeds (Cocker Spaniel/Poodle), it has become extremely common to find crossbreed dogs given labels likewise invented by portmanteau. The tendency for using such labels in a jocular way dates back at least to Queen Elizabeth's dorgis (Dachshund/Corgi). None of these have become recognised by any major registry as purebred breeds, as creating a new breed takes long periods of time, extensive record keeping, and determined breeders. However, as of 2006, the portmanteau words cockapoo and Labradoodle are found in some dictionaries. Label names such as these are most often found in for-sale ads, or on the websites that allow breeders to make up their own portmanteau word names for crossbred litters of puppies. The terms are only loosely descriptive and are seldom consistent; a cross between a Maltese and a Poodle, for example, may be advertised as either a "Maltipoo" or a "Moodle", and the cockapoo is also called a spoodle.

Among the better known dog crossbreeds ("hybrids") are Labradoodles and cockapoos, which each have their own fancier associations and affinity groups. Many Poodle crossbreeds are also popular.

References

  1. ^ Why Are Hybrids Sterile ? - Because of gene evolution
  2. ^ The Science of Hybrids (History)
  3. ^ What is a Wolfdog?
  4. ^ a b Encyclopædia Britannica (online), designer dog
  5. ^ Designer Dogs are the Rage
  6. ^ "hybrid" names, on Celebrity Pets
  7. ^ The Modern Kennel Conundrum by Jon Mooallem, New York Times 02/04/2007
  8. ^ a b My Story: I Designed a Dog, by Wally Conron, in Reader's Digest Magazine pps 28-30, 7/10/2007
  9. ^ Why Crossbreed? from Virginia Tech agricultural extension (cattle breeding)
  10. ^
  11. ^ Diminutive dogs on PoodleHistory.com, referring to "The Complete Dog Book, new and revised edition" (NY: Halcyon House, 1938; first published, 1935) pp. 663-5.
  12. ^ A. R. Michell, Longevity of British breeds of dog and its relationship with sex, size, cardiovascular variables and disease, Vet. Rec., 27 Nov. 1999, S. 625-629 “There was a significant correlation between body weight and longevity. Crossbreeds lived longer than average but several pure breeds lived longer than cross breeds, notably Jack Russell, miniature poodles and whippets” (S. 627) thus only small and toy breeds, as to be expected
  13. ^ P.D. McGreevy & W.F. Nicholas, Some Practical Solutions to Welfare Problems in Pedigree Dog Breeding, Animal Welfare, 1999, Vol 8, 329-331
  14. ^ K9 Magazine (UK), "Designer Dogs Uncovered" issue 16 k9magazine.com

See also

External links