Farm Horizons, August 2012

Cows behaving oddly could mean stray voltage at the dairy

Jennifer Kotila, Staff Writer

As the electric power grid has aged, and more and more electricity is being used to power homes, businesses, and farms, stray voltage is affecting more cows. Stray voltage was first recognized as a problem about 30 years ago, and ongoing research is showing it can be devastating to a dairy.

Today’s dairies use a lot more electricity than in years past, often running industrial-size motors and other large equipment. Some of the powerlines bringing electricity to a farm have not been replaced since they were installed and only powered a couple of light bulbs and small electric motors.

Often, the first sign of stray voltage is odd behavior from cows, according to stray voltage consultants. If left undetected by dairy managers, stray voltage can lead to poor milk production, poor breeding success, and health problems at the dairy. However, stray voltage is something which can be corrected, leading to a much more productive dairy.

Signs of stray voltage

“Any unusual changes in herd behavior may be cause for concern,” said Chuck Untiedt, a dairy farmer from Lakefield who dealt with stray voltage at his dairy, ultimately suing Xcel Energy. Cows experiencing stray voltage will show a number of odd behaviors. “Observations of the dairy animals is of extreme importance so you tune into what your animals are trying to tell you,” he said.

One of the more frequently observed signs that there is a stray voltage problem at a dairy is cows lapping at their water, rather than taking long deep drinks, according to Jerry Lush of Stray Voltage Consulting in Brookings, SD. Farmers will notice the ground around the watering fountain to be wet, and ice will build up in the winter, because of the splashing as cows try to drink, according to Lush.

Other unusual drinking patterns a farmer might notice is a cow walking to get a drink, sensing the water, and then leaving without drinking, Untiedt said. Farmers may also notice abnormal eating behavior, with some areas of the feed bunks being the last to be eaten, or not touched at all, Untiedt added.

A cow’s reluctance to enter the milking parlor, or rushing to exit, can be other signs of stray voltage, according to Untiedt. He added that other signs which will be noticeable when a cow is being milked will be stepping and kicking, abnormal milk let down, dramatic changes in milking time, excessive defecation and urination in the milking parlor, and unexplained swings in milk production from day to day.

Stray voltage will affect a cow’s resistance to other health complications, such as mastitis or displaced abomasum, Untiedt said. If stray voltage is the problem, the cow’s health will not respond appropriately to medical treatment or ration changes, Untiedt said.

Causes of stray voltage on dairy farms

Stray voltage can be caused by “on-farm” and “off-farm” sources. The on-farm sources can be corrected by the owner through proper wiring corrections and good wiring practices, Untiedt said.

“This can vary from tightening connections in the wiring to the buildings, or at a building, to disconnecting a circuit in one of the farm buildings that is causing the problem,” Lush said.

“Off-farm concerns take genuine cooperation from the utilities involved, and possibly even neighbors that may be contributing to a (stray voltage) concern,” Untiedt said.

Stray voltage can come from a number of different sources, such as:

• improper wiring, bonding, grounding, or current flows;

• faulty, failing, or undersized wiring, panels, services, or transformers;

• failure or deterioration of equipment or appliances;

• improperly installed or maintained electric fencers and cow trainers;

• improper neutral and grounding conductor use;

• current leakages;

• corrosion of connections;

• poor or old connections; or

• being too close or too far away from a utility substation.

Although, it only takes one electrical problem to cause a concern, more often there are several layers of problems contributing to stray voltage, and each needs to be diagnosed and resolved, Untiedt said.

What to do when stray voltage is suspected

“Correctly finding and diagnosing the concerns may be difficult,” Untiedt said. “Yesterday’s meters may well not find and document today’s concerns, and concerns may change from day to day, and dairy to dairy – even with the same equipment and installers.”

Dairy farmers who suspect stray voltage should contact a competent person who works with stray voltage to check his farm to see if stray voltage is present, Lush said.

Newer, more sophisticated meters are allowing experts to see the “layers” of problems that may be involved in stray voltage concerns at a dairy, as well as how to correct them, Untiedt said.

Sometimes, problems are resolved by achieving highly-effective isolation from the utility primary neutral current and subsequent earth currents using isolation transformers, changes in distribution, or relocation of distribution. Often, ending stray voltage requires correcting wiring errors.

Both utilities and dairy farmers need to be diligent in correcting electrical problems to overcome issues with stray voltage, with the understanding that power needs change over time, and that wiring is installed to fail safely, but will not remain perfect over time. “Time and usage causes wiring to fail and break. It needs to be monitored, just like the milking systems and all other parts of the dairy,” Untiedt said.

Economic effects of stray voltage

“The economic effects may be minimal, or they may be so devastating that it ends the dairy operation or cripples it so severely that it is extremely difficult to continue,” Untiedt said.

Stray voltage typically lowers the milk production of the dairy herd, therefore affecting the farm’s bottom line, according to Lush. High somatic cell counts will cause the dairy farmer to lose out on the somatic cell count premium, and other health problems lead to high veterinarian costs, he added.

When stray voltage is suspected, it is important to follow through with all corrections that need to be made to reduce electrical stress as much as possible. “Many times we have heard (dairy farmers) say they tried this and thought that helped, and then tried another approach and thought that helped. In the end, they did not lower the level of current sufficiently to remove all the electrical stress and allow the cows to perform as well as they should with the feed, housing, labor, and management provided,” Untiedt said.

Presently, Untiedt is working with Professor Hugh Chester-Jones of the University of Minnesota on a number of dairy farms to see if correction of electrical concerns in the dairy environment can improve their operation. Although no official results or case studies have been released, Untiedt said there have been definite improvements in the dairies participating in the study.

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