The Tibetan Mastiff (Wylie transliteration: do khyi; Lhasa dialect IPA: [tʰòcʰi]) is an ancient dog breed and type of domestic dog (Canis lupus familiaris) originating with nomadic cultures of Tibet, China, Nepal, Ladakh, and Central Asia.
This is an ancient breed. It has been theorized that an early Tibetan dog is the ancestor to all Molossus breeds, although this is disputed by most experts. A highly questionable study at Nanjing Agricultural University's Laboratory of Animal Reproductive Genetics and Molecular Evolution in Nanjing, China, found that while most common dog breeds genetically diverged from the wolf approximately 42,000 years ago, the Tibetan Mastiff genetically diverged from the wolf approximately 58,000 years ago.In the early 19th century, George IV of the United Kingdom owned a pair of Tibetan Mastiffs, and enough of the breed were available in England in 1906 to be shown at the 1906 the Crystal Palace show. However, during the war years, the breed lost favor and focus and nearly died out in England.After 1980, the breed began to gain in popularity worldwide. Although the breed is still considered somewhat uncommon, as more active breeders arose and produced adequate numbers of dogs, various registries and show organizations (FCI, AKC) began to recognize the breed. Since AKC recognition, the number of active breeders has skyrocketed, leading to over-production of puppies, many of which are highly inbred and of questionable quality. Initially, the breed suffered because of the limited gene pool from the original stock, but today's reputable breeders work hard at reducing the genetic problems through selective breeding and the international exchange of new bloodlines. However, some few breeders cling to the practice of inbreeding, do not perform health tests on their breeding stock, and do not support buyers of the puppies they produce. Many puppies and adult dogs end up in shelters and in rescue situations.In 2008, the Tibetan Mastiff competed for the first time in the Westminster Kennel Club Dog Show.A Chinese woman was reported to have spent more than 4 million Renminbi to buy an 18-month-old purebred male Tibetan Mastiff, which she named Yangtze No. 2. In March 2011, a red Tibetan mastiff was reported to have been sold to a 'coal baron' from northern China for 10 million yuan. There have been other similar reports of dogs sold for astronomical prices; however, most of these appear to be breeders' attempts to drive up the prices of their dogs. Photos of dogs shown on web sites are frequently photoshopped to exaggerate color intensity, size, and "bone". Buyers have reported getting their dogs home only to find that bathing removes both color and "hair extensions" from the coat.
Unlike most large breeds, its life expectancy is long, some 10–14 years—at least in some lines. Other, more closely inbred lines, produce short-lived, unhealthy dogs. The breed has fewer genetic health problems than many breeds, but cases can be found of hypothyroidism, entropion, ectropion, distichiasis, skin problems including allergy, autoimmune problems including demodex, Addison's Disease, Cushing's Disease, missing teeth, malocclusion (overbite, underbite, wry mouth), cardiac problems, seizures, epilepsy, progressive retinal atrophy (PRA), cataract, and small ear canals with a tendency for infection. As with most large breeds, some will suffer with elbow or hip dysplasia (canine).Canine inherited demyelinative neuropathy (CIDN), an inherited condition, appeared in one of the prominent lines of Tibetan Mastiffs in the early 1980s. Unfortunately, known carriers were bred extensively and are behind many lines still being actively bred. Because the mode of inheritance appears to be as a simple recessive, continued inbreeding can still produce affected puppies.Hypothyroidism is fairly common in Tibetan Mastiffs, as it is in many large "northern" breeds. They should be tested periodically throughout their lives using a complete thyroid "panel". (Simple T2/T4 testing is virtually useless.) However, because the standard thyroid levels were established using domestic dog breeds, test results must be considered in the context of what is "normal" for the breed, not what is normal across all breeds. Many dogs of this breed will have "low" thyroid values but no clinical symptoms. Vets and owners differ on the relative merits of medicating dogs which test "low", but are completely asymptomatic. Some researchers think that asymptomatic hypothyroidism may have been adaptive in the regions of origin for many breeds, since less nutrition is required for the dog to stay in good condition. Therefore, attempts to eliminate "low thyroid" dogs from the Tibetan Mastiff gene pool may have unintended consequences for the breed.