Suspected chronic fluorosis in a sheep flock.

An estimated average daily intake of 107 g of a lick containing 3.4% of a commercial non-defluorinated rockphosphate, which has an average fluoride content of 2.5% m/m, caused an outbreak of suspected chronic fluorosis in a Döhne Merino sheep flock in the eastern Cape. Thirty seven per cent of the commercial 4-tooth animals were affected, whereas only 17% of the stud component of the same age group, which were in a better nutritional condition, showed clinical signs of fluorosis. Twenty per cent and 33.3% of the 6-tooth wethers and ewes respectively, were affected. Younger sheep and sheep in a relatively poor body condition, were more affected than older sheep and those in a relatively better condition. Non-defluorinated non-registered mineral sources should not be included in supplementary rations for sheep.