A Cross-Sectional Study of Footbath Hygiene and the Application of Footbathing for Control of Bovine Digital Dermatitis on Dairy Farms

Vanhoudt, A., Gillespie, A., Benedictus, L., Logan, F., McAloon, C., Spaninks, M. and Viora, L. (2023) A Cross-Sectional Study of Footbath Hygiene and the Application of Footbathing for Control of Bovine Digital Dermatitis on Dairy Farms. European Buiatrics Congress and ECBHM Jubilee Symposium 2023, Berlin, Germany, 24-26 Aug 2023.

Abstract

Objectives: The objectives of this study were to gauge footbathing regimen compliance with industry recommendations, examine footbath hygiene under field conditions, and measure their efficacy against Treponema bacteria. Materials and methods: Thirty-two dairy herds affected by bovine digital dermatitis (BDD) were recruited by a collaboration of researchers from Utrecht, Glasgow and Dublin. Footbathing practices data was collected using a questionnaire. Researchers attended farms to measure footbath dimensions and collect samples during footbath use approximately every 50 cow passages. Samples were used to measure organic matter content (g/L) (OMC) as a proxy for footbath hygiene. Explanatory variables considered to affect foot hygiene were tested using univariable linear regression to assess associations with the outcome maximum organic matter content (g/L) (OMCmax). One-way analysis of variance was used to assess the association of housing with OMCmax. A subset of samples was evaluated in duplicate using qPCR to measure total bacterial DNA and Treponema spp. DNA content. Total bacterial DNA content of footbath samples was quantified using a 16SrRNA gene qPCR targeting the V5V6 region. The content of bacteria from the Treponema genus, and three species of Treponema commonly associated with BDD (T. medium, T. phagedenis and T. pedis) were quantified in footbath samples using qPCR. Footbath samples collected by Utrecht University were plated on Columbia agar plates supplemented with sheep blood for 22-24 hours at 37°C and colonies counted. Results: A total of 8/32 farms were using footbaths that complied with industry recommendations regarding footbath dimensions, solution depth and litres of solution per cow passage before footbathing began, however 18/32 footbaths were < 3m, and 11/32 footbathing regimes were not providing at least 1 litre of footbathing solution per cow. A total of 30/32 footbaths met the depth criteria at the start of footbathing, however solution depth decreased throughout footbathing resulting in 10/32 having depths <7cm by the end of the session. Organic matter content exceeded 20g/L during footbath use on 16/32 farms. OMCmax decreased by 30% as footbath solution volume increased by one litre per cow (P=0.045). qPCR comparing total bacterial DNA showed samples had lower Ct values at the end of footbathing than at the start. This indicates the presence of more bacterial DNA at the end of footbathing, however not statistically significant on a paired t-test. Furthermore, bacteriological cultures of the Utrecht footbath samples on sheep blood agar were all negative. The qPCR detected Treponema spp. DNA in one duplicate from the final footbath samples on two farms, however, T. medium, T. phagedenis and T. pedis were not detected in any footbath sample. Conclusions: The majority of footbathing regimens did not follow industry recommendations. Increasing footbath solution volume improved footbath hygiene, likely through dilution. The lack of association between OMCmax and explanatory variables expected to influence foot hygiene suggests that defecation is the main source of contamination in footbaths. T. medium, T. phagedenis and T. pedis were not detected by qPCR in any footbath sample. This suggests even footbaths contaminated above 20g/L remain largely effective for inactivation of BDD-associated treponemes.

• Item Type: Conference or Workshop Item
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Viora, Dr Lorenzo
• Authors: Vanhoudt, A., Gillespie, A., Benedictus, L., Logan, F., McAloon, C., Spaninks, M., and Viora, L.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine

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