Effects of Fluoride intoxication on teeth of livestock due to a recent volcanic eruption in Patagonia, Argentina

Abstract

The Puyehue-Cordon Caulle volcanic eruption deposited large amounts of tephra (ashes) on about 36 million ha of Argentina in June of 2011. Tephra were considered chemically innocuous based on water leachates, surface water fluoride levels were determined to be safe, and livestock losses were attributed to inanition and excessive tooth wear. To evaluate chronic effects on livestock, mandibles from animals that died after August 2012 were evaluated. Clearly, these tephra caused dental fluorosis, with bone fluoride levels reaching up to 3,253 ppm. Among sub-adults, tephra caused pathologic wear of newly emerging teeth, with extremely rapid ablation of entire crowns down to underlying pulp cavities. Although initial analyses of water and tephra were interpreted not to present a concern, ruminants as a major component of the affected landscape were shown to be highly susceptible to fluorosis, with average bone level increasing several fold during the first 15 or more months of exposure to tephra. Fluorosis in domestic livestock due to volcanic eruptions has not yet been reported, yet the described impact will affect morbidity, predation susceptibility, body growth, reproductive success and longevity, with associated impact on livestock production systems.