Stray voltage. It’s unseen. It’s hard to identify. And for a growing number of North American dairies, stray voltage is a very real problem that is not easily solved before it causes irreparable damage.
Let’s begin with a look at a few headlines from Canada and the United States.
- “Court Dismisses Family’s Stray Voltage Claim” (AgMedia)
- “Stray Voltage Case Goes to High Court” (LaCrosse Tribune)
- “Jury Awards 2.5 Million to Dairy Farmers in Stray Voltage Case” (Star Tribune)
- “Minnesota Farm Awarded Record $6.3M in ‘Stray Voltage’ Lawsuit” (Forum News Service)
Here is a closer look at specific North American cases.
Canadian Conundrum Goes Nowhere
In Ontario Canada, Chatham-Kent dairy farmers Patrick and Loretta Herbert have been struggling with the stray voltage issue for seven years. For them, one hundred and thirty-two years of family history on the farm may end when they are forced to walk away without solving this heart-wrenching mystery.
In USA Stray Voltage Sparks Current Lawsuits
Across the border, stray voltage is in the courts as dairy farmers seek damages from utility companies. At one point in 2013 there were six active lawsuits in Minnesota. The results were in stark contrast to the Canadian blame game and court dismissals.
In Waverly, a jury awarded 2.5 million to dairy farmers after determining that stray voltage from faulty power company equipment was responsible for production losses. Harlan and Jennifer Poopler and Roy Marshall began their legal fight with Wright-Hennepin Cooperative Electric Association in 2012. At that time, they were awarded $750,000. That award was overturned when the appellate courts ordered a new trial because of errors of the trial court.
In another case, Crow Wing Power of Brainerd was found “negligent in its response to a northern Minnesota farm family’s concerns about stray voltage on their property. The jury awarded Randy and Peggy Norman $4.8 million in economic loss damages and $1.5 million in nuisance damages for a total of $6.3 million, the largest amount ever awarded in a stray voltage case in state history, according to the Normans’ attorneys.”(Read more “Minnesota Farm Awarded Record $6.3M in ‘Stray Voltage’ Lawsuit)
Let’s look back at the Canadian case for examples of arguments put forth by the defending utility companies.
Hydro is “Not Responsible.”
- “We don’t know if it is stray voltage or if it isn’t” (Ontario Hydro spokesperson)
- “We did some tests to make sure it wasn’t our equipment.”( OH spokesperson)
- Hydro One installed a Dairyland Isolater in an attempt to address the issue (paid for by owner). It didn’t help
- “Hydro One is not taking responsibility for its practice of routinely sinking current into the ground throughout rural Ontario.” Affected dairy owners say, “We need to get the antiquated distribution network out of the ground and back on the lines.”
Stray voltage is unique to North America.
The most common source of stray voltage in Canada and the U.S. is neutral current generated by typical power consumption in the grounded neutral electrical distribution system. Electrical distribution in Europe is phase-to-phase and with the rare exception of electric shock from ground faults there is no stray voltage on European farms.
Stray voltage in livestock agriculture is the difference in voltage potential measured between two surfaces that may be contacted simultaneously by an animal. Stray current is the electric current that flows through an animal when it makes simultaneous contact with two surfaces that have different electrical potentials.
Research indicates that most animals are not affected by low levels of stray voltage, but those that are developing “behavioural avoidance” patterns. Sensitive cows may show mild behavioural avoidance at current exposures exceeding two milliamps, corresponding to about 1-2 volts. (Read more: Stray Voltage and Robotic Milking of Dairy Cows)
The electric current can course through the metal on a dairy farm, including through water troughs. This can lead to cows not drinking enough water, not eating enough food and a reduction in milk production, as a result, according to a 2009 publication produced by the University of Wisconsin-Madison. Stray voltage can also cause the animals to produce a stress hormone, decreasing the ability to fight infection.
Six Symptoms of Stray Voltage
- Somatic cell count rises
- Milk production declines
- Cattle are not showing heats
- Cattle are failing to conceive.
- There are unexplained metabolic disease
- Elevated death losses
What Solutions are Available?
Fighting this invisible enemy has tested the ingenuity of farmers, contractors, veterinarians and dairy industry consultants. This is only a starting list, however, here are some that have been tried with varying degrees of success.
- Consultation with veterinarians and other animal advisors
- Water testing
- Dowsing (a.k.a. witching) for electricity
- Changing of feed providers
- Changing power companies
- Learning from autopsies
- Decision to stop farming
Electrical and Structural Solutions
Only a few stray voltage problems can be solved with improved grounding or correction of electrical faults. That does not mean these things cannot play a role, but in most cases either an equipotential grid/plane or a piece of separation/correction equipment is needed.
A slatted floor beside the robot also helps keep the area dry and clean and provides a convenient place to drain wash water and waste milk.
With no maintenance necessary, this is one of the better solutions. There are, however, two possible disadvantages.
- Observation suggests cows are more comfortable walking on solid floors than slatted ones and would avoid slats if possible. If cows are reluctant to step onto the slats, it could be replacing one avoidance problem with another. Using a good quality waffle slat can help solve this potential problem.
- It is costly to add a pit to an existing barn if it is only used to control stray voltage. But in a newly constructed barn a slatted floor area near the robotic milker is a good option. (Read more: Stray Voltage and Robotic Milking of Dairy Cows)
Seeking Government Intervention
In 2005 a Private Member’s Bill (Bill 143) was introduced to Queen’s Park in Canada. It would have forced Hydro One and other distributors to respond quickly to stray voltage problems within a six month period. The bill received unanimous first and second reading support but failed to get final approval prior to an election being called. In 2009 at the request of the Minister of Energy, the Ontario Energy Board ruled that electricity distributors must investigate stray voltage complaints and remedy them if the distribution system is at fault.
Canada: 2009 Ontario Energy Board Ruling
In 2009, the Ontario Energy Board ruled that electricity distributors must examine stray voltage concerns on livestock farms if the farmer can show that stray voltage may be adversely affecting the operation of the livestock farm.
Where an investigation reveals that either:
- ACC [animal contact current] on the farm exceeds 2.0 mA or
- ACV [animal contact voltage] on the farm exceeds 1.0 V
the distributor shall conduct tests to determine whether and the extent to which the distributor’s distribution system is contributing to farm stray voltage measured on the farm.
Where the tests reveal that the distributor’s distribution system is contributing more than 1 mA ACC or 0.5 V ACV to farm stray voltage on a farm, the distributor shall take such steps as may be required to ensure that such contribution does not exceed 1 mA ACC or 0.5 V ACV. (Read more: Stray Voltage and Robotic Milking of Dairy Cows)
One Last Effort
The couple from Chatham, Ontario have tried valiantly and failed so far– to find a solution. As a last effort, they have installed four-by-10-foot steel plates and copper wire buried to within a foot of the soil surface in a ring around the barn. Their hope was that this installation will isolate the dairy barn from any ground current and allow the voltage to be analyzed in real time.
The Bullvine Bottom Line
The crippling effects of stray voltage affect all aspects of the dairy farm and go beyond cow health, milk production and farm profitability. Effective detection devices are the first step. It’s time to go beyond the shocking extremes between doing nothing at all and the awarding millions of dollars in settlements. Stakeholders on both sides of the problem need to take responsibility in seeking and implementing economical and efficient solutions.