Clinical and Pathological Aspects of Fluorine Toxicosis in Cattle*

Abstract

IntroductionFluorine occurs throughout the world in soils, plants, water, and animal tissues.Because of its chemical reactivity, it is found in nature in a combined form.Cattle normally ingest variable amounts of fluorides ( u p to 15 ppm F in dry matter) throughout their lives with no known adverse effects. If amounts above the borderline critical level (which varies with the animal species and the type of fluoride) are ingested over long periods of time, fluorine toxicosis may result. Because fluorine is cumulative in the animal body as long as the animal continues to ingest a constant or increasing amount, the major fluorine problem in livestock has involved chronic toxicosis. This has become an important toxicologic problem in some areas in this and other countries.Various sources may contribute to the total fluorine intake by animals. The most commonly encountered sources of excessive fluoride are: ( 1 ) forages subjected to air-borne contamination in areas near certain industrial operations that heat fluorine-containing materials to high temperatures and expel fluorides; (2) drinking water high in fluoride content; ( 3 ) feed supplements and mineral mixtures high in fluoride content; and (4) vegetation growing on soils high in fluoride content.It is generally accepted that the toxicity of a fluoride compound increases as its aqueous solubility increases. Recent experiments with dairy cattle that were fed controlled amounts of different fluorides have indicated that calcium fluoride is less toxic than sodium fluoride or than hay containing fluoride emitted from a n industrial plant (FIGURE 1).Elevated vegetation levels of fluorine generally result from increased atmospheric fluorides. In at least some cases, a large fraction of these fluorides seems to be deposited on the surface of the leaves and, thus, can be readily removed by rain or washing. Particulate fluorides are more likely to accumulate on plant surfaces than gaseous fluorides. Surface contamination of plants by fluoride in dust o r mud splashed on leaves near the ground may also occur and contribute

Níveis de substituição do fosfato bicálcico pelo monobicálcico em dietas para suínos nas fases de crescimento e terminação

“…Contudo, o excesso de flúor pode provocar incoordenação motora nos suínos (Bellaver et al, 1991). A sensibilidade à intoxicação por flúor obedece a uma escala decrescente: bovinos, caninos, eqüinos, ovinos, suínos e aves (Shupe & Olson, 1983).…”

Fluoride-induced alterations of enamel structure: an experimental study in the miniature pig

“…A characteristic feature of dental fluorosis is a subsurface hypomineralization of the enamel, which today is widely regarded as being caused by a fluoride-induced disturbance of enamel maturation (Aoba and Fejerskov 2002). The pronounced enamel hypomineralization observed in more severe cases of dental fluorosis causes secondary changes, including pathologically increased dental wear (Fejerskov et al 1983(Fejerskov et al , 1991(Fejerskov et al , 1994Shupe and Olson 1983;Kierdorf and Kierdorf 1989;Kierdorf et al 1993Kierdorf et al , 1996Kierdorf et al , 2000. Studies by Fejerskov (1978, 1979) indicated that the enamel surface defects observed in more severe cases of human dental fluorosis do not represent hypoplasias.…”

Palaeopathology in late Pleistocene and early Holocene Central Plains bison: dental enamel hypoplasia, fluoride toxicosis and the archaeological record

“…As bone absorbs fluorine, hydroxyls are replaced on the apatite lattice resulting in a weakened structure prompting compensatory growth that can engender lameness-inducing hyperostosis, osteosclerosis, osteomalacia, and osteoporosis (i.e., osteofluorosis) in long-bones (Obel, 1971;Shupe and Olson, 1983). Among large ruminants, metapodials display the highest incidence of osteofluorosis followed by ribs and mandibles (Singh, 1994;Smith, 2001).…”