Is there stray voltage on your farm?
Stray voltage is a naturally occurring phenomenon that can be felt when a person or animal simultaneously touches two contact points that have differing voltages. Touching the two objects simultaneously creates a closed circuit for current to travel through, and can result in a slight tingling sensation or mild shock.
Often caused by improper grounding, damaged equipment, or faulty wiring, excessive stray voltage can affect cattle stress levels and milk production, as well as cause milking problems. Because of this, farmers are urged to resolve any issues that result in 2 milliamps (mA) or more of stray voltages, even though the majority of cattle aren’t impacted until current reaches 4-5 milliamps.
Know the Signs
Is your livestock affected by stray voltage? Be on the lookout for the following behavioral changes:
- Reduced feed and/or water intake
- Refusal to enter the milking parlor
- Nervousness or excessive movement during milking
- Excessive defecation or urination in milking parlor
- Slow milk let down
- Incomplete milk out
Some farmers have reported additional impacts to their livestock, including reproductive issues, mastitis, and increased somatic cell counts. Researchers were not able to replicate or verify these claims in any of their studies.
Detecting Stray Voltage
Your electric company or a trained electrical contractor can inspect your existing wiring system and monitor electrical activity over an extended period of time to determine whether stray voltage levels are a concern on your farm. If stray voltage is detected, the trained professional will attempt to determine the source of the issue, and repair or reduce the issue.
Common Contact Points for Stray Voltage
Wet surfaces and metal in cow traffic areas are likely candidates for sources of stray voltage. Common contact points can include:
- Water bowl to floor
- Water bowl to stall
- Stall/parlor steel to floor
- Heated waterer to floor
- Feed bunk to floor
- Caldwell, Emily. “Stray voltage affects cow behavior, milk production.” Progressive Dairyman.
- “Is Stray Voltage on Your Farm.” Wisconsin Public Service.
- “Measuring Stray Voltage on the Farm.” Wisconsin Public Service.