"ELECTRIC COWS"
Could Electric Current from Wireline Services Distress Dairy Cows?
by Roger Tokarz
Outside Plant Magazine January 2000
ospmag.com
A time ago, my friend Barry Dardis was working for PTI Communications. Some of his duties
included Inductive Coordination Electrical Protection (ICEP). He received a call from the
company's midwest division and was asked to research protector grounding methods at dairy
farms. It seemed that the company had come under scrutiny in the "dairy farm stray voltage
phenomenon." The question was, should the company disconnect protectors from the power
ground at dairy farms? Barry began to glean information and reports from various sources in the
area to answer that question.
The reports detailed how cows are far more sensitive to electric shock than people. Apparently,
a couple of volts are enough to cause great distress and strange behavior. If a cow comes to
associate electric shock with a milking parlor, it becomes increasingly difficult to get the cow
through the door. Once inside, there is a great deal of dancing and bellowing. However, it gets
worse. When the cow receives the anticipated shock, it loses all control of its bodily functions.
The cows under watch were dairy cows. Their job, of course, was to produce milk. As you
might imagine, connecting these upset cows to the milking machine was one very messy rodeo.
Once the machines are finally connected to the upset cows, the dairyman gets very little milk.
After the milking is done, the dairyman and his family must also take great care not to get
between the cows and the door, as these stressed animals tend to leave the milking parlor very
quickly.
The report said that 95% of these cow disturbances were obvious electrical problems that were
immediately found and fixed. The usual causes were errors in milking parlor wiring and insulation
failure in pumps and other devices around the farm.
However, a couple of cases described faults that were found in equipment owned by the power
utility. Naturally, these events were widely publicized and some lawsuits, in fact, produced large
settlements for the dairy farmers.
Background
Initially, symptoms of stray voltage at the dairy included extreme nervousness, reduced milk
production, and changes in eating and drinking habits among the cows. These same symptoms,
of course, could have been caused by other conditions the cows were subjected to. Poisonous
weeds in the pasture, poor feed, bad water or disease all could have contributed to the cows'
strange behavior. As human nature had it, however, when milk production fell off, some farmers
preferred to look at mysterious electrical phenomenon more closely than an obvious, less exotic
cause.
This behavior produced a need for experts and, in the scientific and technical world, experts
have a way of appearing overnight. Soon, people were scurrying around the areas' milking
parlors and farmyards, measuring everything from DC to microwaves. Often, the investigators
found nothing in the way of electrical wiring error or equipment malfunction. Still, the farmers
insisted there was no other possible cause for the cows' strange behavior and urged investigators
to keep looking for the source.
The next logical step was to use more sensitive equipment to discover more and more sources of
minute electrical disturbances. It was at this juncture that even telephone companies came under
suspicion.
The cash-generating potential of this situation did not go unnoticed by lawyers and consultants of
one kind or another. Measuring wizards dusted off their oscilloscopes and galvanometers and
took to the field. University professors, who seldom find a way to escape the lecture hall, also
joined the fray. It seemed that the mere hint of a problem on a dairy farm resulted in a flock of
people determined to solve the problem and an equal number of others ready to represent the
owner should legal action be required.
Report Highlights
The report was interesting in a number of ways. For one, the problem was examined by a wide
variety of people. These people included agricultural agents, who knew a lot about cows and
nothing about electricity, to electrical engineers who knew a lot about electricity and nothing
about cows. Predictably, the electrical engineers made many cow assumptions and the
agricultural people made a lot of electrical assumptions. And everyone wrote a paper.
Another interesting part of the report was the assumptions made. To say some of the
assumptions defied the laws of physics is an understatement. My friend, Barry, had considerable
experience in the measurement of mysterious electrical currents, and he immediately raised some
questions about the findings. After mulling the information over for a few days, he called the
authors of select papers to gain a better understanding of the situation.
The highlight of Barry's research was a discussion he had with an expert who will remain
unnamed. This expert said in a factual manner that a cow had a resistance of about 500 ohms
and that a voltage of 0.5 volts was enough to cause problems for the bovine. He didn't share the
particulars, such as how he attached the meter to the cow, how many cows were measured in
his study, or whether the cows were willing participants.
Again, drawing on his experience, Barry thought that, based on physics, the manner to find the
current through a 500-ohm cow with 0.5 volts applied would be a simple matter. But Barry was
quickly derailed by the expert's next statement delivered in an all-knowing tone, "Of course, you
can't use Ohms Law because the cow itself produces a voltage."
Much giggling and snorting punctuated Barry's description of the rest of his conversation.
However, the gist of it was: "No one knows how much voltage is produced by a cow."
According to the expert, "The output of a cow cannot be measured by any known means, so no
one knows whether it is AC or DC, or where the measuring points might be on the cow." When
Barry asked the expert HOW he knew the voltage existed, he stated factually, "We just know."
Methodology
Later, I related the information to a rancher friend in Montana, who was not at all surprised at
the prospect of cows carrying some sort of electrical potential. In fact, he said that he had a
couple of cows he thought might indeed be charging themselves on the electric fence.
The existence of a mysterious electrical quantity that cannot be measured certainly invites
speculation. Could it be that this force, which we shall call Vb (Voltage bovine), has something
to do with the odd general behavior of cattle? And, if a cow really is a walking voltage source,
might the cows be somehow adversely affecting one another?
To test the theory, some more assumptions must be made. Should Vb exist, the odds are that it
is DC rather than AC. If this is the case, here are some possible social effects.
If Vb is in the vertical plane, a cow's feet would be at one polarity and the upper part of the
cow, including the head and tail, would be at the opposite polarity. The question is: Could two of
these beasts get together, series aiding, and hurt one another? With the vertical voltage model,
there seems little chance, since it is doubtful that two cows routinely position themselves so each
has its nose on the other's feet.
A horizontal voltage distribution seems more likely and presents quite a different set of
possibilities. In this case, the tail is at one potential and the head at the opposite potential. If all
the heads are positive and the tails negative, then a bunch of cows touching head to tail might
create enough voltage to do some useful work, like running the barn lights. Perhaps milking stalls
could be arranged to take advantage of this free source of energy. Care should be exercised,
however, as completing such a circuit might cause enough flow to kill all of the
cows.
Conclusion
While discussion and deliberation about the electric cows could continue into the year 2002, the
bottom line finding was that the Wisconsin Telephone Company was not responsible for the
electrical disturbance of dairy cows.
Obviously, more research is necessary, and it won't be easy. No doubt, somewhere in the
hallowed halls of science, physics and agriculture, there is some researcher who will get to the
bottom of Vb, or Voltage bovine. Thankfully, it's not me.
Roger Tokarz can be reached via e-mail: tadcon@foxinternet.com. Barry Dardis can be reached
via e-mail: darbgtf@mcn.net |
