A foot bath design for large grazing herds

By Chesterton, R. N., 17th International Symposium and 9th International Conference on Lameness in Ruminants, 2013
Research Paper Web Link / URL:
Description
Introduction Footbathing is an essential part of Bovine Digital Dermatitis (BDD) control (Blowey 2010). In large herds footbaths are often underutilized if they affect cow-flow through the milking parlor. In many herds contamination of the footbath quickly reduces the effectiveness of the solution. The discovery of a BDD problem on dairy farms in Chile provided an opportunity to design foot baths for large outdoor grazing herds. The aim of this study is to first identify the problems of the existing footbaths on the farms. Then to design a permanent foot bath that could be easily built into an existing facility. Materials and Methods The first step was to observe and video cow flow through the existing baths to identify possible causes of poor cow flow and excessive contamination. A footbath was then designed and trialed on 15 farms. Farm managers were asked to rate the cow flow. Cow flow through the new baths was videoed on 9 farms and defecations counted to estimate contamination. Results Eight design features causing poor cow flow through the existing footbaths were noted: · A step down into footbaths built below the level of the walking surface. · A step down out of footbaths built up above the level of the walking surface. · Sloping gradients into or out of footbaths · Slippery walking surfaces before, in or after footbaths · Metal or plastic floors of portable footbaths · Rounded top on the nib wall surrounding footbaths · Footbaths built on a diversion from the usual exit pathway · Narrow single-cow-width baths All the features above that affected cow flow also caused increased contamination. Four other design features causing increased contamination were noted: · Baths longer than 3 metres, or baths with a water pre-bath, became more contaminated. · Small volumes relative to the size of the herd. · Footbaths positioned at the entrance to the cowshed · Small drain outlet resulting in poor cleaning Figure 1 Design of new footbaths 213 The resulting new design criteria are as below. 1) Construct in the exit race 2) The footbath is part of the exit race itself 3) Wide footbaths – at least 1.5 metres wide. 4) The length must be at least 2.5 metres and a maximum of 3 metres. 5) The floor of the bath must be the same level as the approach and exit concrete. 6) 20 cm concrete block walls. 7) The solution depth : 8 - 10 cm minimum (ref) 8) Tops of the blocks flat with only the sharp edges ground off. 9) The volume of the bath allows for one litre per cow in the herd. 10) 10 - 12 cm drain hole in the lowest corner On the 15 farms, thirteen managers rated cow flow as “good”, two managers as “average” and none as “poor”. On 9 farms the average percentage of cows defecating into the footbath was 3.2% (ranging from 1.4% to 5.8%). Discussion Farmers, even if they understand the need, are often reluctant to use footbaths because of the effect on cow flow out of the dairy. There were a surprising number of reasons identified that were causing a reluctance of cows to walk through existing footbaths in this study. When these were addressed the result was reasonable cow flow and minimal contamination. Contamination was a low enough level that the bath solution was able to be used twice in consecutive milkings. This design is cheap to build on an existing concrete track, or can be easily included in the design of a new shed. References Blowey RW 2010 Non-healing hoof lesions in dairy cows, Veterinary Record doi: 10.1136/vr.
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