dry mouth), cardiac problems, seizures, epilepsy, progressive retinal atrophy (PRA), cataracts, and small ear canals with a tendency for infection. As with most large breeds, some will suffer with elbow or hip dysplasia. 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". 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. History Originally these dogs were used to protect Buddhist monasteries and monks of Tibet from animals such as bears, wolves and snow leopards. The Tibetan Mastiff is a phenotypically distinct dog breed that was bred as a flock guardian in the high altitudes of the Himalayas and the Tibetan Plateaus. Meer Izzut-oollah (1872) wrote of the Tibetan Mastiff: In the early 20th century, the Prince of Wales, George, introduced a pair of Tibetan Mastiffs to the United Kingdom, with the breed becoming prevalent enough in England in 1906 to be shown at the Crystal Palace show. However, during the war years, the breed lost favor and focus and nearly died out in England. The breed has been gaining in popularity worldwide since 1980. 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. In 2008, the Tibetan Mastiff competed for the first time in the Westminster Kennel Club Dog Show. Since AKC recognition, the number of active breeders has skyrocketed, leading to over-breeding 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. By 2015, due to excessive breeding and