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Equine Researchers Investigating Silicate Associated Osteoporosis

March 13, 2015

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A horse with signs of SAO.

Equine researchers at UC Davis School of Veterinary Medicine need your help in investigating a devastating disease in horses—Silicate Associated Osteoporosis or SAO. As suggested by the name, the disease involves both the lung and bone organ systems. 

The disease occurs in horses in specific geographic regions of California where soils contain high concentrations of certain toxic forms of the mineral crystal, silica dioxide. When inhaled, the crystals cause chronic lung disease, much like COPD (chronic obstructive pulmonary disease) or silicosis in humans. Drought conditions in the state exacerbate the problem as vegetation dries out and more dust is exposed. 

Affected horses suffer profound osteoporosis which gradually weakens the skeleton, causing progressive unspecific and shifting lameness, with subsequent bone deformities and sudden fractures. The lung issues cause flared nostrils and shortness of breath in some horses, and a reduced tolerance for exercise. With no known cure, most afflicted horses are euthanized for humane reasons. While the disease can affect horses of all ages, UC Davis researchers are focused on those aged 10 and older. 

Over the past seven years, UC Davis researchers and collaborating veterinarians have characterized the disease and determined diagnostic techniques useful for detecting affected horses. However, the mechanism that causes the bone disease and the relationship of the bone disease to the lung disease remains unknown. Understanding this will provide insight into possible treatment, better diagnostic techniques and prevention, and could be useful for understanding similar diseases in people and other animals.

You can help by contacting UC Davis about horses whose disease warrants humane euthanasia due to poor quality of life due to SAO, or other conditions. Donated horses will be humanely euthanized in the large animal clinic for immediate collection of study samples. For more details, please contact Dr. Regina Zavodovskaya at; 530-754-0156.