The association between fluoride concentrations and spontaneous humeral fracture in first-lactation dairy cows: results from two New Zealand studies

Authors: Wehrle-Martinez A, Dittmer KE, Back PJ, Rogers CW, Weston JF, Jeyakumar P, Pereira RV, Poppenga R, Taylor HS, Lawrence KE
Publication: New Zealand Veterinary Journal, Volume 73, Issue 2, pp 143-147, Mar 2025
Publisher: Taylor and Francis

Animal type: Cattle, Cattle - dairy, Cattle - heifer
Article class: Brief Communication

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Abstract:

Aim: To assess whether the fluoride concentration in the humeri of first-lactation, 2-year-old dairy cows with a spontaneous humeral fracture is significantly different from that of firstlactation, 2-year-old dairy cows without a humeral fracture.

Methods: Two studies were conducted, the first with nine bone samples from 2-year-old, firstcalving dairy cows with a humeral fracture (all from the Waikato region) age-matched with seven control bone samples from the Waikato, Bay of Plenty and Manawatū-Whanganui regions. The second study used 26 bone samples from 2-year-old, first-lactation dairy cows with a humeral fracture (from the Otago, Canterbury, Southland, West Coast, Waikato and Manawatū-Whanganui regions) age-matched with 14 control bone samples (all from the Manawatū-Whanganui region or unknown). Control bone samples were from first-lactation, 2-year-old dairy cows that did not have humeral fractures. Bone fluoride concentration was quantified for all samples.

Results: The median fluoride concentration of humeri from first-lactation, 2-year-old dairy cows with a humeral fracture was significantly higher than humeri from unaffected control cows in both studies. In Study 1, the median bone fluoride concentration was 599 (IQR 562.7–763.5) mg/kg from case cows and 296.6 (IQR: 191.2–391.7) mg/kg from control cows (p < 0.001), and in Study 2 the median bone fluoride concentration from case and control cows was 415 (IQR: 312.5–515) mg/kg and 290 (IQR: 262.5–410) mg/kg (p = 0.04) respectively.

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.

KEYWORDS: Humeral fracture, cows, fluoride, bone, New Zealand

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