Electricity and Livestock

Electricity has helped make the dairy industry what it is today. Yet electricity demands our respect and the use of electricity on a dairy farm requires special attention. Todd-Wadena has been working with dairy farmers to diagnose and mitigate stray voltage for nearly two decades. In the early years there was little information on the appropriate testing procedures, mitigation methods, and levels of concern. After literally hundreds of scientific studies and reports on the subject, it is safe to say that stray voltage is a well documented and well understood aspect of dairy farming.Cow looking through a fence uid

The Questions & Answers printed below provide a brief description of stray voltage. For more details, read ‘A Stray Voltage Primer’, by Al Haman, PE/CEO & Principal Engineer of STAR Energy Services, Alexandria, MN.

Q. What is stray voltage?

A. Stray voltage is a difference in voltage measured between two surfaces that may be contacted simultaneously by animal. Although stray voltage is present on all active distribution systems, humans usually do not notice it. Some types of livestock, especially dairy cows, are particularly sensitive to it.

Q. What are the symptoms?

A. A dairy cow affected by stray voltage may show symptoms such as:

  • Nervousness during milking
  • Reluctance to use metal waterers or feeders
  • Unexplained drops in milk production
  • Incomplete milk letdown
  • Increased mastitis
  • Elevated somatic cell count

However, dairy producers should remember that these behavior changes also can occur due to problems with milking equipment, changes in milking routine, spoilage of feed or pollution of drinking water. Therefore, all potential sources for behavioral changes should be investigated.

Q. What causes stray voltage?

A. Causes can vary. Some common sources, found both on and off the farm, include:

  • Improper wiring
  • Poor grounding
  • Unbalanced 120 volt loads
  • Faulty equipment
  • Poor or corroded connections

Q. What should I do if I suspect stray voltage on my farm?

A. Start the problem-solving process by taking all of the following actions:

  • Contact the cooperative office at 218-631-3120 or 800-321-8932 and explain your concerns.
  • Have a licensed electrician inspect the wiring on your farm.
  • Make all necessary wiring connections. Remember that the safety concerns related to some wiring problems are more important than the stray voltage problem. By correcting safety hazards, you may solve a large part, if not all, of your stray voltage problems.
  • Have your milking equipment dealer check out your milking system.
  • Contact your veterinarian to help you address any herd health concerns that may or may not be related to stray voltage.


For more information: ‘A Stray Voltage Primer’, by Al Haman, PE/CEO & Principal Engineer of STAR Energy Services, Alexandria, MN