Sunday, 27 September 2009

Dairy Cows very Sensitive to Stray Electricity

Dairy Cows are 15 times more sensitive to stray voltage than humans. Stray voltage leaks into milking parlours due to faulty electric motors or poor fittings on electrical equipment either in or near Milking Parlours.

Some UK dairy farmers know they have a problem but can neither locate nor fix the stray voltage. Others are unaware they have a problem or that it could be related to stray voltage. However there is a problem of poor cow behaviour in the parlour, elevated Bulk Milk Cell Counts & excessive mastitis due to teat end damage.

What are the signs that Stray Voltage may be a problem?

Milking Cows unsettled on the milking platform, stamping & excessive manure during milking.

Rust & bubbling of the metal at the base of steel pipes in contact with concrete.

Cows unwilling to cross gaps in the yard or concrete especially where there is exposed metal eg bridge in rotary parlour.

Cows sniffing pipework

Unusual rubbing & shine on some pipework (where cows are rubbing or backing off other pipes)

Excessive teat end damage & High Bulk Milk Cell Counts
This week Pasture to Profit Discussion Groups in England had 4 valuable days with Steve Corkill from CSL Taranaki NZ.
In the UK we lack skilled people who can identify & fix stray voltage in milking parlours. Steve & Tim brought with them a sensitive meter that measured stray voltage. They checked for stray voltage in a number of milking parlours......around motors, water pipes, across gaps in concrete. They could detect electric fence units & water heaters that were leaking neutral voltage.
Stray voltage of 0.5Volt will unsettle cows. Up to 0.8 Volts will create damage to teat ends. Between 1.5 & 2.0 Volts cows will refuse go near the offending pipework where they might touch & be frightened.
Testing the Milk Pump is especially important as the milk pump is often leaking stray voltage & it is effectively in touch with the cows udder & teats. Variable speed control units for milk pumps & Vaccumn pumps dramatically reduce the risk of stray voltage. Check out Varivac on the CSL website.
Turn off electric fences & Water Heaters during milking to reduce the risk. Electric Fence units should be 30m from the parlour & properly earthed.
Steve we need people like you or trained by you to test for Stray voltage in UK parlours. More importantly we want the problem fixed.
Fantastic meetings what great information & visual demonstration! Well done.

1 comment:

  1. All too often when concrete is being laid in a new parlour the earthing has not been adequate. It is suggested that you weld all the various components together when making the parlour, taking especial care that the reinforcing / earth under the cows feet is not pushed down too deep into the poured concrete ( needs to be about 1.0 to 1.5 inches max from the surface of the concrete). Often it has been found that their is a current "gap" between the collecting yard and the parlour. This can be overcome by grooving the collecting yard in a fan shape from the parlour and sinking a copper or other good conducter into the surface of the concrete ( again shallow ) and by connecting it up to the parlour earthing so creating a more gradual "current gradient" into the parlour. It can sometimes also be an issue at the parlour exit, causing cows to hang back / stop exiting and thus slowing up milking routines.
    This has had a major impact in improving situations on some parlours over here and in Ireland.
    Ian Browne