Objective: It was investigated whether usage of the biocidal product T-Hexx Dragonhyde (Hydromer, Branchburg, NJ, USA) could influence the prevalence of digital dermatitis (DD).
Material and methods: On a dairy farm (110 milking cows) 48 dairy cows without lameness were selected randomly for a test group or a control (negative) group, respectively. A high prevalence of DD (70-80%) was documented over a period of 2 months, during which four examinations were made, with an interval of 16-21 days between each examination. The respective grade of the DD-lesion on the hind hoofs was documented according to a scoring scheme. After precleaning the claws with water, the test group passed through a hoof bath containing T-Hexx Dragonhyde on 2 days per week at two milking times on each day, whereas the claws of control animals were cleaned using only a water bath. Splashes contaminating the animals and the environment were documented photographically and evaluated. Bacteriological examinations of the water bath and the T-Hexx-bath were performed after increasing numbers of animals had passed through the baths.
Results: Between and within groups no statistically significant differences in the prevalence of DD were found. DD-lesion scoring did not show any difference between the groups. With increasing numbers of animals having passed through the water bath, there was a significant increase in colony-forming units per millilitre and of enterobacteriaceae. In the T-Hexx Dragonhyde footbath, bacterial contamination remained below the detection limit at all times. The coloured splashes of the footbath were visible up to the level of the udder and teats.
Conclusion and clinical relevance: The prevalence of DD was not influenced by the 2% or 4% concentration of the biocidal product in the footbath. Thus the microbiocidal effect of the solution did not lead to an efficient reduction in bacteria on the hoof. To demonstrate a potential preventive effect on DD, future studies would require herds with lower prevalence and a higher sample size. However, when applying footbaths there is the general risk of milk contamination or causing mastitis.