Ranch Application: Chlorine Dioxide Teat Disinfectant: A Clinical Study on Bactericidal Efficacy and Safety in Dairy Cows in Comparison with an Iodine Glycerin Disinfectant

https://pubmed.ncbi.nlm.nih.gov/41594499/


Published: January 20, 2026, in the journal Animals (Basel).
What the study was about:
Researchers tested a new teat disinfectant made with chlorine dioxide (used to clean cow teats after milking to prevent infections) and compared it directly to a common traditional one based on iodine glycerin. The goal was to check if the chlorine dioxide version worked as well (or better) at killing bacteria and was safe for the cows' teats and overall udder health.
How they did it:
It was a randomized controlled trial on dairy cows. They looked at two setups:

Long-term use on 100 cows (natural exposure over time).
Direct teat surface disinfection on 40 cows.
They measured:
Somatic cell count (SCC — a sign of udder inflammation/infection).
Teat skin condition (dryness, roughness, hyperkeratosis/thickening).
How well it killed common mastitis bacteria: Staphylococcus aureus, Escherichia coli, and Streptococcus spp.
Main results:
For udder health (high SCC rates), chlorine dioxide performed similarly to iodine glycerin (3.57% vs. 4.50% of cases exceeding the threshold at day 10; no significant difference).
Teat skin health (dryness, roughness, hyperkeratosis) showed no meaningful differences between the two disinfectants over time.
Chlorine dioxide killed bacteria more effectively in lab measurements: higher reduction in bacterial numbers (log10 reduction of 2.14 vs. 1.93 for iodine; statistically significant).
It completely eradicated (100%) all tested bacteria isolates, while iodine glycerin was very close (99.84–100%).
What the authors concluded:
The chlorine dioxide teat disinfectant works as well as (and in some bacterial tests, slightly better than) the iodine glycerin one for preventing infections. It also keeps teats in good condition and may have advantages like being more sustainable and leaving fewer residues. They suggest more studies in different farms to confirm the findings.
In short: This on-farm study found chlorine dioxide to be a safe and effective alternative disinfectant for cow teats, with strong bacteria-killing power and no worse effects on skin or udder health compared to the usual iodine product.