Tuesday, March 30, 2010

Tibetan Mastiff

The Tibetan Mastiff, also known as the Do-Khyi or Tsang-khyi, is an ancient breed which descended from large Chinese dogs in the second millennium B.C. It may have arrived in Asia with the armies of Attila the Hun or Genghis Khan. The Tibetan Mastiff is an influential breed, thought to be an ancestor of the Saint Bernard, Newfoundland, Pug, and others. Its original function was as a guardian for sheep flocks, monasteries, and entire villages. Marco Polo met some Tibetan Mastiffs on his trips throughout Asia, describing them as ‘tall as a donkey with a voice as powerful as that of a lion.’ The Tibetan Mastiff was unknown outside of Tibet until 1847, when Queen Victoria received one as a gift from the Viceroy of India. Tibetan Mastiffs became endangered in their native country in 1959 when China invaded Tibet. Two Tibetan Mastiffs were delivered to President Eisenhower by the Dalai Lama as a preservation effort, but they did not successfully produce any breeding lines. Larger numbers of Tibetan Mastiffs were finally imported to the U.S. and Europe from India and Nepal in the 1970’s. The Tibetan Mastiff was accepted under the American Kennel Club’s Miscellaneous category in 2005. It is still somewhat rare, but breeders are successfully increasing the Tibetan Mastiff’s number through selective crossbreeding of international stock.
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Life Expectancy Unlike most large breeds, its life expectancy is long, some 10-14 years. The breed has fewer genetic health problems than many breeds, but cases can be found of hypothyroidism, entropion, ectropion, skin problems including allergies, autoimmune problems including demodex, missing teeth, malocclusion (overbite or underbite), cardiac problems, 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, although this has not been a major problem in the Tibetan Mastiff. Another concern includes canine inherited demyelinative neuropathy (CIDN), a rare inherited neural disease that appeared in one bloodline in the early 1980s.
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Canine Hip Dysplasia (CHD) takes many forms, e.g., the femoral head ("ball") may not fit well into the acetabulum ("socket"); the ligament connecting the two may be lax, allowing dislocation; there may be no femoral head at all. Not all forms cause clinical signs. Very active, well-muscled dogs with no femoral heads may show no impairment. Their owners may be unaware of their dogs' "hip dysplasia" unless/until there is a reason to x-ray the hips.

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As with all dog breeds, hip dysplasia is caused by the interaction of genes and environment. Inheritance of CHD appears to be polygenic, i.e., it is caused by more than one gene. Mode of inheritance (dominant, recessive, dominant with incomplete penetrance, etc.)has not been determined but may be different in different breeds. Rapid growth and weight gain in puppies may trigger or exacerbate a genetic tendency to all sorts of skeletal problems. Many TM breeders recommend against feeding "puppy food" and especially against feeding "large-breed" puppy food, as these concoctions may contain too many calories, leading to fat puppies. Some breeders and owners believe that supplementation with Vitamin C may prevent the development of CHD even in dogs with the genes for it.

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Canine Inherited Demyelinative Neuropathy is an inherited condition that appeared in one of the prominent lines of Tibetan Mastiffs in the early 1980s. CIDN afffect the peripheral nervous system. Nerve fibers are unable to transmit impulses from the spinal cord to the muscles because of the breakdown of the myelin sheath. Starting at approximately six weeks of age, affected pups begin to lose the ability to walk or even stand. Progression of the condition can take anywhere from a few days to two weeks. Information from "The Tibetan Mastiff" by Ann Rohrer and Cathy J. Flamholtz

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Because this condition is inherited as a simple autosomal recessive, it is virtually impossible to completely eliminate it from the gene pool. One known carrier was bred to over 30 times, producing at least 134 direct descendants. Many descendants of this dog are still being bred so there is always the risk - however slim - of producing more affected puppies. Breeders need to be cautious about pairing up any two descendants of this dog...

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Hypothyroidism is fairly common in Tibetan Mastiffs, as it is in many large "Northern" breeds. TMs 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 TMs will have "low" thyroid values but no clinical symptoms. Vets - and owners - differ on the relative merits of medicating dogs who "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 TM gene pool may have unintended consequences for the breed.

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In affected dogs, symptoms may include decreased activity and playing, increased sleeping, weight gain, poor skin and coat condition such as flaking and scaling, a "yeasty" smell to the coat, frequent ear infections, and negative changes in temperament. Fortunately, this condition is easily treated by the use of daily thyroid supplementation.

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Osteochondritis Dessicans is a skeletal defect in which the cartilage lifts off the bone, becomes thickened and cracked, causes inflammation and pain, and in severe cases degeneration of the joint. This conditions strikes males more than females. Keeping an affected puppy lean may help but surgery may be required to relieve pain.

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Panosteitis is inflammation of the bones that strikes young dogs. The animal will become lame in one leg and then the inflammation will shift to a different leg. This is one condition that corrects itself over time, and only pain medication is needed.

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Hypertrophic Osteodystrophy (HOD) is a condition that affects young large breed dogs. It is very painful and prognosis is fair to poor due to recurring episodes of the condition. Clinical signs of HOD include fever, lack of appetite, and depression. Lameness may vary from mild to severe. With multiple limbs affected, the dog may be reluctant to stand or walk. HOD may be mistaken for Panosteitis without proper diagnosis.

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Treatment is only supportive. Intravenous fluids are usually required to keep the patient hydrated. Nutritional support is provided with a feeding tube if the dog refuses to eat for five or more days. Pain is controlled with narcotics and NSAIDs. Antibiotics are used if the dog has signs of pneumonia or other bacterial infections. If the bones become twisted due to growth plate damage, corrective surgery may be indicated. Because the distemper vaccination has been implicated, inoculation should be delayed until the pet has been in remission for a couple of months. Information from
http://www.vetsurgerycentral.com/hod.htm
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Ear Infections can be serious and the dog should be taken to the vet if you see it shaking its head or scratching more than normal. Tibetan Mastiffs have pendant ears, making them more prone to ear infections. The vet needs to determine the cause, and may prescribe antibiotics and/or ear drops. Some ear infections are contagious to other dogs if they involve mites or some bacteria.

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Tibetan Mastiff

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Tibetan Mastiff Dog Club Directory
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- A non-profit organization established for the protection and preservation of the Tibetan Mastiff in the United States. Breed and club information can be found along with many pictures.
- Tibetan mastiff kennel from Hungary.
- Breeder from Great Britain, introducing the dogs with pictures and pedigree information.
- Breeder of Quality Tibetan Mastiffs in Illinois USA.
- Raising dogs for guarding livestock. Photographs and training tips. Galva, Illinois.
- Introducing the dogs with pictures, showresults and breeding news. Located in Czech Republic.
- Pictures, pedigrees, show results, and litter announcements. India.
- Seng Khri Tibet Mastiff Kennel , located in Hungary.
- Photographs of their dogs, breed history, news, and links. Yorkshire, United Kingdom.
- Images, characteristics, breed history, and standards.
- Continental Kennel Club breed standard with breed information and articles.
- Pictures, puppy news and show results.
- Kennel and breed histories, characteristics, and breeding schedule. Sweden.
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