Phosphate fertiliser contains 4% fluoride. Super Phosphate is applied all over New Zealand pasture as fertiliser every year on most farms. As a result, fluoride is building up in the soil causing harm to grazing animals and harm to the top soil. See study below for more detailed information and links to other relevant studies.
Conclusions and clinical relevance
Although there are limitations to this study due to the unbalanced regional distribution of cases and controls, the results indicate that sub-clinical fluoride toxicosis may be linked to spontaneous humeral fractures in first-lactation dairy cows in New Zealand. Further research is required to determine if bone fluoride concentrations play a role in the pathogenesis of these fractures.
https://www.tandfonline.com/doi/full/10.1080/00480169.2024.2418929#abstract