Stray Voltage Effects

Animal reactions to stray voltage will vary depending on the severity of the problem. These symptoms are common in dairy operations:

  • Uneven milk production
  • Cows reluctant to enter the parlor
  • Cows nervous while in the parlor
  • Increased mastitis
    (Stray voltage doesn't cause mastitis. Mastitis can develop regardless of the presence of voltage. Stray voltage can reduce the effectiveness of mastitis treatments.)
  • Reduced feeding in the parlor
  • Reluctance to drink water
  • Increased manure deposition in the parlor
  • Decreased milk production

Each of these symptoms is associated with stress, and can lead to reduced appetite and disease. In any case, a drop in milk production is certainly a possibility. There are other factors that can lead to these same symptoms including:

  • Mistreatment,
  • Milking machine problems,
  • Disease,
  • Sanitation, and
  • Nutritional disorders.

If stray voltage is identified, be advised that the influence of low level voltages on dairy cows is not known with any degree of precision. However, it is generally believed that AC voltages in excess of 0.5 volt are enough to warrant concern and to justify corrective measures.

Even if the voltage during milking is less than 0.5 volt, it should be checked to determine if higher voltages exist during specific hours, days, seasons of the year, or weather conditions. But by and large, if voltages do not exceed 0.5 volt during milking there is generally no cause for concern.

Incidentally, research has shown that dairy cows have a higher tolerance for DC voltages. One volt DC justifies corrective actions.