Tuesday, June 17, 2008

Stray Voltage -- Who Knew?

For four years now I have had dairy cows here at the farm.  Over the course of tending to them and milking them twice daily during those many seasons, I feel that I have amassed a  fair amount of bovine experience.  I certainly am aware of my shortcomings but at least I knew where they were.  I was humbled this week by a bizarre cow problem.
The dairy building is a small concrete building that I had built three years ago to chill the milk, store it, bottle it and to hold the dairy equipment.  On one side of it is a small portico that the cows pass through on their way to the milking parlor adjacent to the dairy.  It is a concrete slab that is integral to the milk house and covered by a metal roof.
This past wet, rainy week one of the cows came up to the porch, had two of her hoofs on the muddy ground and two on the concrete slab.  Immediately she began to buckle and writhe.  I thought she had something stuck in one of her hoofs at first and proceeded to encourage her to continue through the porch so I could check it out. She continued to dance across the concrete appearing at this point to be having a heart attack if cows can have such a condition.  
It was frightening and fascinating all at the same time.  Once she passed over the concrete and onto the sidewalk leading into the milking parlor it appeared to cease.  The next cow, however, appeared to have the same problem minutes later.  At this point it was apparent that it was not a condition that one cows was afflicted by, but rather an environmental issue.
At the same time as the bovine-concrete revulsion, the large blast chiller that cools the milk began having odd problems;  blowing circuits and shutting down at the end of its cycle.  I surmised an electrical problem in the milk house.
My local friendly electrician Jason was called and informed of this bizarre occurrence. I expected him to tell me that he felt I was insane, but even if he felt that way, he kept it to himself and arrived that afternoon to investigate.  As there are few dairies on this suburban island, his expertise was more in wiring media rooms for the latest flat screen TV than in hooking up dairy barns. Luckily he is a curious guy and made some calls, brought out a voltage meter and began poking around.
As it happens there is an entire part of the Electrical Code that deals with dairy barns.  Cows, I know now, are extremely sensitive to, among other things, stray voltage.  They have the ability to pick up a half of a volt of electricity as it flows through a slab of concrete.  At one stray volt cows can get so disturbed as to dry up and cease producing milk.  We were getting readings of as much as two volts off of the metal roof and galvanized downspouts that connect to the concrete pad.  Maybe it was my thick rubber boots, but on my hands and knees I was unable to detect anything on this seemingly dull, un-pulsing concrete slab.  
Jason hooked up a few grounding wires, made plans to sink a few deep grounding rods, but mostly we just looked for ways to keep the cows away from the building.  Luckily cows other great qualities are the ability to never forget anything and to revel in routine.  The next morning after the great shocking trek to milking, neither Boo nor Francesca had any interest in coming near the milk house.  They appear very docile and loving, but 850 pounds of bovine anchored into the ground with pointed hoofs is no match for my slender frame attempting to pull them.
The cows have found a new path to milking that they are happy with, Jason is reading up on the electrical dairy protocol and I have another notch on my dairyman's belt.  

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