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Crossbreed dogs or designer dogs are mixed-breed dogs which have been intentionally bred from two or more recognized dog breeds and not from dogs with no purebred ancestors, but have not been artificially bred to each other enough to breed true and be recognized as a breed in their own right. ==Designer dogs== The ''Encyclopædia Britannica'' 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.〔(Encyclopædia Britannica (online), designer dog )〕 The primary identifying mark of a crossbred "designer dog' is that the resulting puppies are called by a portmanteau word made up of syllables (or sounds) from the breed names of the two purebred parents, such as Schnoodle (''Schn''auzer and p''oodle'' cross).〔 Other purebred breeds are being crossed to provide designer dogs described with an endless range of created labels, such as the Puggle (''Pug'' and Bea''gle'' cross). There are even complex crosses (with multiple breeds in recent ancestry) being labeled in this manner, such as German Chusky (German Shepherd Dog, Husky, Chow Chow).〔("hybrid" names, on Celebrity Pets )〕 Like children in a family, a percentage of designer dogs with the same breed ancestry will look similar to each other, even though crossbreeding does not result in as uniform a phenotype as the breeding of purebreds. Often even pups in the same litter will look quite different. Another defining characteristic of designer dogs is that they are usually bred as companions and pets. Working and hunting dogs deliberately crossbred for a particular working purpose are not generally given portmanteau names; they are most often referred to by a type (not breed) name, such as Eurohounds (racing sled dogs) or Lurchers (hunting dogs). These dogs could be considered only as cross breeds, not as designer animals, since appearance is not the main reason for them to be bred. An exception to this is the Labradoodle, which although having a Portmanteau name, is often used as a Guide or Assistance dog〔(Colchester: More than puppy love! (From Gazette) ). Gazette-news.co.uk (2008-06-17). Retrieved on 2013-05-31.〕〔Altonn, Helen. (2004-06-28) (Honolulu Star-Bulletin Hawaii News ). Starbulletin.com. Retrieved on 2013-05-31.〕 as well as being popular family dogs. Although designer dogs are often selected by owners for their novelty, reputable breeders sometimes use crossbreeding in an attempt to reduce the incidence of certain hereditary problems found in the purebred breeds, 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."〔(The Modern Kennel Conundrum by Jon Mooallem, The New York Times 02/04/2007 )〕 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)."〔(Why Crossbreed? from Virginia Tech agricultural extension (cattle 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?"〔(My Story: I Designed a Dog, by Wally Conron, in Reader's Digest Magazine pps 28-30, 8/9/2010 )〕 ''Designer dog'' puppies sometimes bring higher prices than the purebreds from which they are bred,.〔 * (Small Business Trends: Pet Industry Trends for 2008 By Laura Bennett, 12/10/2007 ) "2008 will see the rapid growth of the puppy farm crossbreeds to take advantage of the inflated prices people are paying for these dogs." * (Not all cute and cuddly in land of 'designer dogs,' by Melissa Patterson, Chicago Tribune, July 23, 2008 ) crossbreed designer dog puppies "often go for more money than purebreds, which can range from $200 to $2,000 per dog." * (The Independent (Newspaper, online) "Hounded out: Fur and loathing in the dog world" by Ed Caesar, Thursday, 8 March 2007 ) "the stampede to acquire one (designer dog) has become so furious that puppies now sell for as much as £2,000." * (Designer Dogs are the Rage on designerdoggies.com ) "the Beagle is one of the lowest priced purebred dogs, yet the Puggle often sells for much more than the purebred Pug."〕 The fanciers of designer dogs respond 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.〔(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. )〕 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 crossbred dog 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 compared to purebred dogs. "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" (thus only small and toy breeds, as to be expected).〔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〕 In general 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."〔P.D. McGreevy & W.F. Nicholas, Some Practical Solutions to Welfare Problems in Pedigree Dog Breeding, Animal Welfare, 1999, Vol 8, 329-331〕 Many breeders of designer dogs take advantage of the fact that people are impressed by a pet that they believe offers them an elevated social status, such as other "designer" goods do. "It's human nature to aspire to own something a little different, a little fancy or in short supply."〔(K9 Magazine (UK), "Designer Dogs Uncovered" issue 16 k9magazine.com )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dog crossbreed」の詳細全文を読む スポンサード リンク
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