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Low levels of step voltage (SV), a potential difference affecting dairy cows, may impact health and milk production. Studies show higher SV on farms with lower milk yields, suggesting a link to electrical issues and soil resistivity.

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Area of Science:

  • Agricultural Engineering
  • Animal Science
  • Environmental Health

Background:

  • The
  • Stray voltage
  • is a recognized issue in dairy farming.
  • Published literature suggests even low step voltage (SV) levels, below 0.5 V, can negatively affect cow health and milk production over time.
  • Values as low as 10 mV may be significant.

Purpose of the Study:

  • To investigate the relationship between step voltage (SV) and milk production on Minnesota dairy farms.
  • To analyze the correlation between SV, soil resistivity (rho), and farm electrical systems.
  • To determine potential causes of reduced milk production related to electrical environments.

Main Methods:

  • Conducted a measurement program on 19 Minnesota dairy farms (9 high-production, 10 low-production) in summer 1997.
  • Measured step voltage (SV) between the front and hind hooves of dairy cows.
  • Measured soil resistivity (rho) in farm fields.
  • Analyzed electrical distribution systems and barn environments.

Main Results:

  • Step voltage (SV) was 4.2 times higher on low-production (LP) farms compared to high-production (HP) farms.
  • Soil resistivity (rho) was 3.4 times higher on LP farms than HP farms.
  • Only three farms exhibited SV greater than 9 mV; low production on these farms might be linked to other factors like vaccination status.

Conclusions:

  • A significant correlation exists between higher soil resistivity, increased step voltage (SV), and lower milk production in dairy farms.
  • The origin of SV in barns may be linked to external electrical distribution systems and field soil resistivity, not just barn flooring.
  • Further laboratory research is essential to confirm the long-term health and productivity impacts of low-level step voltage exposure in dairy cows.