Use of copper sulfate and zinc sulfate in footbaths on oregon dairies - a case study
Dairy farmers use footbaths to control diseases of the hoof. When the footbaths are changed, the solutions are dumped into the dairy manure handling system and applied to fields in the liquid manure system. The objective for this project was to survey 30 dairy farms in Oregon to evaluate CuSO4 and ZnSO4 use in footbaths. Using CuSO4 and ZnSO4 in footbaths is creating potential long-term environmental and cropping challenges on many Oregon dairies.
Soil samples were collected from 2 major fields at 15 cm deep and all samples were analyzed for Cu and Zn. Forages grown on the farm were sampled and analyzed for Cu and Zn, and manure was collected directly from milk cows and from the liquid manure storage system.
All forages, soils, and manure were analyzed for Cu and Zn. Soil Cu concentrations ranged from 0.7 to 34.7 ppm, with an average of 5.7 ± 6.6 ppm. Soil Zn concentrations ranged from 0.6 to 41.8 ppm, with an average of 10.1 ± 9.3 ppm. Forage Cu concentrations ranged from 1 to 10 ppm, with an average of 3.4 ± 2.1 ppm, and forage Zn ranged from 3 to 51 ppm, with an average of 13.8 ± 10.3 ppm. Copper concentrations in fresh manure directly from milking cows were very consistent, at 10 ppm, and Cu in the manure storage ranged from 2 to 58 ppm, with an average of 10.3 ± 12ppm. The use of CuSO4 and ZnSO4 in footbaths on dairies in Oregon continues to be a common practice. More than 75% of dairy soils tested were considered high (>2 ppm) in Cu concentration and 38% were extremely high (>5 ppm). Using CuSO4 and ZnSO4 in footbaths is creating potential long-term environmental and cropping challenges on many Oregon dairies.
Authors: T. W. Downing ,* K. Stiglbauer ,† M. J. Gamroth ,† and J. Hart ‡
* Department of Animal Sciences, Oregon State University, Tillamook 97141; and † Department of Animal Sciences, and ‡ Department of Crop and Soil Science, Oregon State University, Corvallis 97331
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