Silicate-Associated Osteoporosis in Horses

Horses living in specific areas of California are at risk for silicate-associated osteoporosis (SAO), a disorder related to soils with a high concentration of silica dioxide. The condition is also known as bone fragility syndrome.

Horses that inhale dust laden with silica dioxide can develop a chronic lung problem similar to silicosis in humans. Breathing becomes more labored in affected horses. As the disease progresses, they show flared nostrils, shortness of breath, and exercise intolerance.

SAO also affects the skeletal system. Horses may develop osteoporosis, bone deformities, a swayback, shifting lameness, and spontaneous bone fractures. No treatment has been found, and horses with advanced SAO are euthanized.

Veterinary researchers at UC-Davis are conducting an ongoing study of the cause, diagnostic techniques, and treatment options for SAO. The researchers are accepting affected horses for the study. Owners wishing to donate horses are asked to contact Dr. Regina Zavadovskaya at rzav@ucdavis.edu or 530-754-0156.