Measuring the Initial Concentration of Formalin in Walk-through Footbaths in Dairy Herds

In a field study the changes in formalin concentration in walkthrough footbaths in 18 dairy herds (n = 66.8, [40-140]) were determined by sampling 3 consecutive days. The footbaths were sampled just after preparation and every time, immediately after the dairy cows had passed the footbaths. The concentration was estimated by sampling, immediately filtering and analysing (gas-chromatography) the formalin-concentration in the samples from the walk-through footbaths. The initial concentration was reduced by 50% after 2,4 days and this is in this study comparable with 300-320 cow passages. The milking cows' enthusiasm for walking through the footbaths did not influence the decrease of the formalin concentration...