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What Do We Know AboutStray Voltage?
Terms, Sources, Animal Research,Terms, Sources, Animal Research,Transients, High Frequency, Field
Studies, Earth Currents, EMF,
Douglas J. Reinemann, Ph.D.
University of Wisconsin Madison
Milking Research and Instruction Lab UW-MRIL
Don't Let Stray VoltageRuin Your Life
Hope
Trust
ResponsibilityResponsibility
Measure
ReasonTechnical RealityResearch
EmotionCompassion
Correct Farm WiringCorrect Distribution WiringUtility IsolatorEGS
Is it SafeIt is Technically EffectiveWill it help the cows
EGSIsolation TransformerGrounding Ring.
If You Think You Have AStray Voltage Problem
Watch the Cows.
Measure Voltage.
Find the Source.Find the Source.
Find the safest, simplest way to fixit.
If You Think You Have AStray Voltage Problem
If you Cannot Measure Cow ContactVoltage
Stray Voltage Can Be A ProblemStray Voltage Can Be A Problem
If its There You can Measure it andreduce it
Consider Other Sources ofProblems
Its Not Always the Problem
Learned Behavior Avoid Contact
Introduction to Stray Voltage
Prevent
How to:
DetectReduce
Stray Voltage
What Is Stray Voltage?A difference in voltage measuredbetween two surfaces that may becontacted simultaneously by ananimal (USDA, 1992).
It IS a Mild ShockIt IS a Mild Shockcaused by a contact voltage
It is NOT Electric/Magnetic Fields(EMF)
It is NOT "Ground CurrentsUnless they produce contact voltage
How Can Neutral Voltage BeReduced?
Reduce Resistance
Size of Conductor
Quality of jumpers and connectionsQuality of jumpers and connections
Number and quality of grounds
Reduce Current
Balance loads
Fix faults
The source of Stray Voltage is voltage developed by currentflowing on the resistance of the grounded neutral system
Animal Response to StrayVoltage
Avoidancebehavior
Milk production
Well documented
Documented onlyfor extremeexposure
Somatic cells
Reproduction
Milkout problems
exposure
Not documented
Not documented
Not documented
Reasonable Level
Zero tolerance is
Impossible
ExpensiveExpensive
May be Dangerous
Not warranted base on researchresults
Sensitivity to 50/60 Hz
Sensitivity to High Frequencies
Types of Voltage/Current
60 Hz voltage
Steady
Motor StartsMotor Starts
High Frequency Transients
Fencers, Trainers, Crowd Gates
Equipment Switching
Conclusions From USDA,1992 for 60 Hz Voltage.Perception begins 1 to 2 mA (0.5-2 V).
Cows become conditioned.Behavioral problems may persist afterBehavioral problems may persist afterstimulus is removed.
Keep Cow Contact Voltage < 2- 4 V.Consider cost of reducing voltage.
Economic/Non-Economic Effect.
Milking machine an unlikely pathway.
Wisconsin Rules andRegulations
PSCW stray voltage order.
The "level of concern" for livestock ismore than 2 milli-amps of steadystate, 60 Hz AC, RMS current inmore than 2 milli-amps of steadystate, 60 Hz AC, RMS current inanimal contact locations, measuredbetween two points that livestock maycontact simultaneously.
1 V = 2 mA x 500 Ohms.
Literature Review and Synthesis ofResearch Findings on the Impact ofStray Voltage on Farm Operations
Douglas J. Reinemann, Ph.d.
Professor of Biological SystemsEngineering
University of Wisconsin-Madison
1. Scope of this Report
Literature review
Pathways whereby stray voltage canaffect animals
Symptoms indicative of stray voltageSymptoms indicative of stray voltage
Minimum voltage (or current) level atwhich impacts can be expected.
Measures for mitigating stray voltage
Review of regulatory measures
Ways That Stray, or Tingle, VoltageCan Impact Farm Operations
Direct effects
Mild behavioral reactions = sensation
Involuntary muscle contraction = twitching
Intense behavioral responses = painIntense behavioral responses = pain
Severity depends onamount of electrical current (milliAmps) flowingthrough the animals body
Body pathway
Individual animal Sensitivity
Indirect effects
Animals avoiding certain exposure locationsReduced water intake if exposure is required foranimals to access watering devices,
Reduced feed intake if exposure is required foranimals to accesses feeding devices or locations.Reduced feed intake if exposure is required foranimals to accesses feeding devices or locations.
Difficulty of moving or handling animals in areasof voltage/current exposure
Release of stress hormones produced bycontact with painful stimuli
2. Overview of Electrical Exposure and thePhysiology of Animal Contact Voltage and
CurrentCurrent
Basic concepts of voltage, current, andresistance
Ohms law = relationship between
Voltage, Current and Resistance
If voltage (across animal contact points) isincreased, the current flowing through theanimal will increaseanimal will increase
If resistance (of contact points) isincreased, the current flowing through theanimal will decrease
1 milliAmp = 1/1000th of an amp
R
R
R
R
R
R
R
Elements of the Source Circuit
Vs = Voltage Source(I*R on neutral wire)
Rs = SourceResistance
Rp1 = Path
R
R
Rp1 = PathResistance 1
Rp2 = PathResistance 2
Voc = Open Circuitor Source Voltage
V
R
V
Elements of the AnimalCircuit
mA = currentthrough animal
Rc1 = contactResistance (Muzzle
R
Resistance (Muzzleor front hooves)
Ra = bodyResistance
Rc2 = contactresistance (allhooves or rearhooves)
R
VR
V
mA
V(source) R(Source) R(animal +contact)
AnimalContactvoltage
Animalcontactcurrent
1 volt 100 Ohms 500 Ohms 0.8 Volts 1.7
Importance of ProperCircuit Identification
1 volt 100 Ohms 500 Ohms 0.8 Volts 1.7milliAmps
1 volt 100 Ohms 1000 Ohms 0.9 Volts 0.9milliamps
1 volt 1000 Ohms 1000 Ohms 0.5 Volts 0.5milliamps
The Problem of Contact Resistance
The most variable part of the electrical circuit
Contact resistances will increase with:smaller contact surface area
reduced contact surface pressure
drier contact surfaces
the amount of debris on contact pointthe amount of debris on contact point
resistance value of the debris at the contactmargin
The accepted practice by researchers andregulators has been to assume worst-case(lowest practical values) for contactresistances.
Sensory and Motor NerveStimulation and Response
1.5
2
2.5
3
3.5
Ne
rve
Re
spo
nse
0
0.5
1
1.5
0 1 2 3 4
Ne
rve
Re
spo
nse
Current Exposure
Threshold of Response(so that they do not fire all the time)
The Bio-mechanics of NerveStimulation
As current levels increase
No response below threshold
Sensory responses just aboveSensory responses just abovethreshold
Tingling, warmth, startle
Motor response
Involuntary muscle contraction, twitch
Pain
Behavioral ResponsesEach animal will have a behavioral responsethreshold to current exposure for a particularcontact pathway
Studies have used a variety of behavioral responsethresholds
most sensitive behavioral indicators of perceptionmost sensitive behavioral indicators of perceptionhigh variability, rapid acclimation to unfamiliar
annoyance and/or aversionChange eating / drinking behaviors
Current applied in a periodic mannerrepeated series of startle behaviors
Involuntary muscle contractionMost repeatable, Higher current threshold than sensation
Literature Review 1962-2008
61 Studies of voltage/current applicationto cows
26 Studies of voltage/currentapplication to other farm species
8 Studies of Cow Trainers and Fencers
application to other farm species
8 Studies of Cow Trainers and Fencers
Studies Reviewed forData Collection
Data analysis
Repeatability
Research Groups Farm Animals andElectrical Exposures
USU Minnesota - Gustafson/ Cloud/ Brennan/
Appleman/Henke-DrenkardCornell - Aneshansley/Gorewit/Price/Wilson/
Ludington/SouthwickMichigan - Surbrook/Kirk/Althouse/FickU Missouri - Currence/ Winter/ Stevens/ DickJohns Hopkins - ReillyPurdue - Albright
CanadaOntario- RushenAlberta - ThorneMcGill Burchard/ Rodriquez/New Liskeard - GumprichAustraliaDamaskNew ZealandPhillips, Whittlestone,Purdue - Albright
UWEX Hendrickson / KammelUSDA Beltsville - LefcourtWashington - Lee et al.USDA ARS StetsonU of Wisconsin - Reinemann/ Scheffield/ Wiltbank/
LeMire/ Armentano/ McGuirk/ Laughlin/PSCW - Dasho/ Cook/ ReinesDATCP - Kasper/ Roberts/Hansen/RyderMinnesota PUC - Hendrickson/ PatochQuigleyHalvorsonGodcharles
Phillips, Whittlestone,Woolford, SalisburyGermanyBergstenOswaldSwedenAlgersHultgrenPehrsonFranceAroParisTech - Roussel, Ragalma
29 groups more than 70 people
New Zealand: Phillips,1962
First published Cow study
Voltages on milking plants in New Zealand0 to 20 V - most between 3 and 10 V.
Sources of voltage: unbalanced loads andSources of voltage: unbalanced loads andHigh resistance neutrals
Voltage applied teat-to-rear hooves
After these experiments 3 volts waschosen as a likely minimum level forresponse.
New Zealand: Woolford, 1972
Use Current Exposure in an attempt toreduce variability of responses
front to rear hooves
wetted flank to 4-hooveswetted flank to 4-hooves
changes in cow behavioral when currentsreached 3 to 8 milliAmpere
judged to be uncomfortable for currentsof 4.5 to 12 milliAmpere
New Zealand: Whttlestone,1975
Operant conditioning system as a moreobjective method of measuringbehavioral responses
cows turned on an electric current bycows turned on an electric current bypressing a second manipulanda in order toreceive crushed barley
behaviors changed with currents of
6 mA for the udder, 7 mA for one teat
6 mA for rump, 4 mA chest area.
Early North American Studies
Craine, 1975
Groups of 70 and 30 cows exposed tovoltages on a waterer ranging from 0(control treatment) to 8 volts.(control treatment) to 8 volts.
Mild aversion noted at 3 volts
Suppression of water above 4 volts
8-volt treatment discontinued after 1 daybecause many cows refused to drink
United States Department ofAgriculture Research
Lefcourt (1982a) EKG patches shaved areas onthe front and rear legs
Reduce the problem of contact resistance
Four cows mild response at about 3 mA
One cow mild responded to 0.7 mA (cut in skin?)
Lefcourt (1982b) 6 cows to subjected to 5 mAbefore and during milking
Milk yield and milking time decreased forintermittent current
Continuous treatment had a variable effect on milkyield, milking time and hormonal responses
some cows seemed to adapt and enjoy stimulation.
USDA: Lefcourt (1985)7 cows at 3.6 mA and 6 cows to 6.0 mA at a.m. andp.m. milkings for 7 days, subdermal probe
One cow removed from the 6.0 mA group because ofsevere behavioral responses
Milk yield, milking time, and Wisconsin Mastitis Testscores were not affected
Peak milk flow rate increased slightlyPeak milk flow rate increased slightly
Behavioral events increased
Short Term Heart rate elevation
Concluded negative effects of electrical shock onmilk production or mammary health most likely notrelated directly to shock
severe behavior would result in managementproblems.
USDA: Lefcourt (1986)
Seven lactating cows exposed to 60 Hz currents of 0,2.5, 5.0, 7.5, 10, then 12.5 mA, biweekly.
As mA increased, cows became more agitated and
two cows not shocked at 12.5 mA due to severe behavioralresponsesresponses
Short term Heart rate increased at 10 mA and 12.5 mA
Prolactin, norepinephrine and glucocorticoids wereunaffected
Epinephrine doubled in two exceptional cows at 10 mA
Dramatic behavioral responses not correlated withsignificant or prolonged physiological responses
Electrical exposure not considered a reliable way toinduce stress in cows.
The University of MinnesotaElectrical resistance of milking machinecomponents
milk hose 30,000 Ohms to 80,000 Ohms
minimum resistance from the claw throughthe cow to the floor was 3,000 Ohms.the cow to the floor was 3,000 Ohms.
8 pathways through dairy cows
mean path 359 ohms for a mouth-allhooves pathway to 738 ohms for a front-rear hooves pathway
U Minn. suppression of alearned response to obtain food
6.0 mA front-rear hooves shock
Muzzle-all-hooves shock as low as 1.0 mAsuppressed plate pressing behavior
learned escape response to a front-rearlearned escape response to a front-rearhooves shock above a normal activitylevel occurred between 2.0 and 3.0 mA.
exposure conditions were not typical offarm exposures.
Appleman and Gustafson1985 review
0.7 V (60 Hz rms)
endocrine response > 3 V or 8mA (60 Hz rms)
Resistance 350 to 1700 ohmsfor different pathways
Updated review 1987Revised based on additional research
milking machine not likely pathway, highresistance
no direct and causal relationship betweenno direct and causal relationship betweenvoltage exposures and milkingperformance and animal health
Problems may occur
mouth-all hooves > 1.0 volt.
step potential > 2.0-volt
Thresholds to DC current(Gustafson 1988)
behavioral response to DC pulsewidths ranging from 0.1 to 300millisecondsmilliseconds
Body resistance decreased
more current required to elicitbehavioral responses
with narrower pulse widths.
Research at Cornell I
0, 0.5, 1, 2 and 4 V applied to waterbowls for 21 days
Two cows out of 6 did not drink for 36hours at 4VTwo cows out of 6 did not drink for 36hours at 4V
All 28 others drank normal amounts ofwater within 2 days.
Higher voltage = more delay to drink thefirst gallon of water.
Cornell II
3, 4, 5 and 6 V to water bowls for 48 hours84 cows Heifers
2 heifers at V and 2 heifers at 6 V did not drinkfor 36 hours.for 36 hours.
Within 2 days those that drank were drinkingamounts that were not significantly differentfrom the time before voltage was placed on thewater bowl.
Higher voltage = more delay to drink the firstgallon of water.
Cornell III
Discontinuous voltages 5 V and 8Vapplied water bowls to rear hooves.
Five temporal patterns were used to applyFive temporal patterns were used to applyvoltage of 50% of the time
Drinking patterns not consistent but nosignificant change in amount of waterconsumed.
Cornell IV
0, 1, 2 or 4V applied from waterer to a metalgrid (front hooves) over a full lactation (305days).
4 groups of 10 cows each4 groups of 10 cows each
Milk weights, SCC, milk fat, protein, feedconsumption and water intake showed notsignificant differences between groups.
Voltages did not significantly influence cowhealth or reproductive performance.
Cornell V
Current applied to teats during milking.
Heifers kicked at milking machines whencurrent exceeded 5 to 12 mA.current exceeded 5 to 12 mA.
Older cows kicked at milking machines at8 to 18 mA.
New Liskeard College of AgriculturalTechnology
Groups of 30 cows with 112 day exposrues
continuous low-level voltage w/ 2 periods ofhigher levels:
0.30 V and 1.0 V0.30 V and 1.0 V
0.75 V and 2.5 V
0.75 V and 5.0 V
level (1) higher milk fat percentage
Milking time longer for level (2)
residual effect on milk production 2 periods after thetreatment at level (3)
Concluded that up to 5.0 V in well managed tie-stall dairyoperations unlikely to cause observable changes in cowmilk production or behaviour.
USDA 1991 Summary
Consensus opinion of 15 credibleresearchers
distressed that our research resultswere being misinterpretedwere being misinterpreted
Recommend action levels from 2 to 4Volts
As conservative as possible to account forindirect losses due to problems resultingfrom inappropriate response of farmers tochanges in animal behavior
USDA 1991 Summary
To relate voltage measurements tocurrent, the worst case (500 Ohms) andmore realistic (1000 Ohms) Resistancswere used.were used.
Attempts to reduce cow contact voltagesto below 0.5 to 1.0 V are unwarranted,and totally unnecessary
No contradiction to these findings in2003 NRAES review.
Synthesis of OEB Review of ResearchFindings
Compilation of all knownexperiments in which responses tovoltage or current exposure weredocumentedvoltage or current exposure weredocumented
Spanning 1962 to 2007 (45 Years)
From Research Groups Around theWorld
Over 100 Scientists Represented
40%
50%
60%
70%
80%
90%
100%
Pe
rce
nto
fCo
ws
Re
spo
nd
ing
First Behavioral Response,n=365
Discomfort, n = 133
Aversion, N =36
0%
10%
20%
30%
40%
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Pe
rce
nto
fCo
ws
Re
spo
nd
ing
Current Level (mA, rms)
Over 450 cows withconstant CURRENT exposure
Many studies report on single animal responses
Behavior response thresholds varyModerate: Blink of an eye, nose twitch
Pronounced: Involuntary muscle contraction
Aversive: Stop DrinkingAversive: Stop Drinking
Most behavioral response thresholds betweenfrom 2 and 8 milliAmps (60 Hz rms)
One study reported moderate responses at 1 mA witha nose press to metal plate (current concentration)
Aversion occurs at higher levels than behavioralresponse
Over 300 cows withconstant VOLTAGE exposure
Most studies report on group average rather thansingle animal responses
Many studies report moderate behavioral betweenthe range from 2 and 8 volts (60 hz rms)
Studies using metallic waterer - metallic floor plateStudies using metallic waterer - metallic floor platefound some delays to drink at 1 Volt
Studies using concrete floor did not report behavioralchanges at 1 Volts
Some studies report severe aversion of a fewanimals between 4 and 8 volts
Refusal to drink for up to 36 hours
Kicking at milking unit
Over 300 cows with constant voltageexposure
Most responses 2 to 8 Volts
Over 450 cows with constant currentexposure
Most responses 2 to 8 MilliampsMost responses 2 to 8 Milliamps
Over 750 Cows Tested
1000 Ohms reasonable estimate of cow+ contact resistance in real-worldsituations
May be some unusual cases as low as500 Ohms
Animal Response to StrayVoltage
Avoidance behavior
Milk production
Well documented
Documented onlyfor extremeexposure
Somatic cells
Reproduction
Milkout problems
Stress Hormones
exposure
Not documented
Not documented
Only at very highlevels
Only at very highlevels
Exposure Conditions Requiredto Produce an Effect
Adverse effect requires BOTH annoyingcurrent AND forced exposure
Contact resistance500 ohms is worst case500 ohms is worst case
1000 Ohms is typical
Dry contacts or bedding will increasecontact resistance
LocationAreas vital to normal daily activities
Times / dayAnnoying stimulus must occur frequently
Levels That Affect Farmperformance
Current exposure < 3 mA mayproduce mild behavioral changes in asmall percentage of cowssmall percentage of cows
Corresponding to < 2 to 3 Volts
Aversive behaviors likely short-lived
No physiological changes
Changes likley undetectable on mostfarms
Levels That Affect Farmperformance
Current exposure from 3 to 6 mA mayproduce observable behavioral changes insome cows
Corresponding to 3 to 6 VoltsCorresponding to 3 to 6 Volts
May produce short term changes ineating/drinking for some cows dependingon location and time of exposure
Likely difficult to detect
Aversive behaviors likely short-lived
May produce mild increase in stresshormones in some cows
Levels That Affect Farmperformance
Current exposure above 6 mA likely toproduce some behavioral changes in mostcows and pronounced behaviors in somecowscows
Corresponding to > 6 Volts
Likely to produce changes in eating /drinking for some cows depending onlocation and time of exposure
May be detectable on some farms
May produce increase in stress hormonesin some cows
Diagnosis
Animal behavior or other symptomsCANNOT be used to diagnose strayvoltage problems
All known responses to stray voltageAll known responses to stray voltageexposure can be produced by other causes
The ONLY WAY to determine if strayvoltage is a potential cause is to performelectrical testing
Voltage/Current Sensitivity byContact Location and Animal Type
Exposure at watering devicesExposure at feeding devicesExposure at feeding devicesExposure during milkingExposure at building transitionsExposure in resting areas,pastures and other FarmLocations
Exposure at watering devices
Likely location for voltage exposureMetallic water systems connected to grounding systemArea necessary for animalsWorst case (lowest) contact resistances on clean, wetfloorsfloorsMetallic / heated watering devices highest riskAlternate watering locations w/ lower voltage reduceor eliminate effectsNon Metallic watering devices much lower risk highcontact resistanceEquipotential Planes required around watering devicesSevere aversion > 4 Volts / 8 mA
Exposure at feeding locations
Floor feeding unlikely location forproblems
High resistance of feedLow level step potentials if metal infloorLow level step potentials if metal infloor
Metallic, electrical feeding devicespossible location for aversion
Resistance values at muzzle and floorhigher than for metallic wateringdevices
Learned Behavior Avoid Contact
Exposure during milking
Highly unlikely locationfor problems
Milk hose has very high resistanceMilk hose has very high resistance
Milking parlors usually well bonded(equipotential)
Body resistances high for hide/stallcontact
Exposure at building transitions
Severe wiring problems mayproduce aversive step potentials ifequipotential plane not installed
Contact resistances likely > 1000Contact resistances likely > 1000Ohms
May make animal handling moredifficult but unlikely to affectfeeding / drinking behaviors
Exposure in resting areas, pastures andother Farm Locations
Highly unlikely location forproblemsHigh resistance contacts DryHigh resistance contacts Drybedding to hide / hoovesstep potentials very low comparedto contact with electrical devicesMetal in floors acts asequipotential
On-Farm Mitigation Measures
Farm Wiring
Equipotential PlanesEquipotential Planes
Voltage Suppression andFilters
On farm isolation
Utility Mitigation Measures
Distribution Wiring
Neutral IsolationNeutral Isolation
Mitigating Other Sources
7. Regulatory Approaches andGuidelines to Reducing the Impact ofStray Voltage on Farm Operations
Wisconsin
Michigan
VermontVermont
Idaho
Minnesota
New York
Pennsylvania
Cornell VI
The average current required to cause cows tostop drinking ranges from 4.9 to 132 mA rmsfor steady 60 to 30k Hz currents
38 to 80 mA peak for DC pulses from 0.4 to 0.138 to 80 mA peak for DC pulses from 0.4 to 0.1ms in duration.
8.2, 9.3, 9.7 and 10.7 mA rms for steady, 30cycles, 15 cycles and 6 cycles of 60 Hz
180 Hz +60 Hz components peak currentexplained responses better than rms
60 Hz + DC bias of 0.5 to 2 V did notsubstantially change the response
Sensitivity to 60 Hz andother waveforms
ASAE 99-3152 Aneshansley and Gorwit
Cows less sensitive to high frequency andshort duration currents
No effect of DC bias on sensitivityNo effect of DC bias on sensitivity
Some differences between RMS sensitivitywith VERY LARGE harmonic content.
No difference when measured as peak values
Explained by other research.
100.00
1000.00
10000.00
Thre
shold
Curr
ent,
(Peak
mA
)Cornell and Wisconsin Data Compared
1.00
10.00
10 100 1,000 10,000 100,000
Frequency (Hz)
Thre
shold
Curr
ent,
(Peak
mA
)
Cornell VII
0, 1, 2 and 4 V applied between waterers andrear hooves
16 animals with histories of sub-clinical mastitis
16 animals challenged with mastitis organism
No significant change in milk production, feedconsumption, milk fat and protein, SCC, bloodchemistry, milk microbiology and serumcortisol
Effects of Voltage/Currentexposure on Mastitis
ASAE 99-3151 Gorewit andAneshansley
0, 1, 2 and 4 V applied to water bowl0, 1, 2 and 4 V applied to water bowl
Teats dipped after milking withStrep uberis culture
Exposure of up to 4 Volts did notpromote clinical mastitis
Dairy Cow Response to ElectricalEnvironment
UW Research UpdateUW Research Update
Douglas J. Reinemann, Ph.D. Professor ofBiological Systems Engineering
University of Wisconsin-Madisonwww.uwex.edu/uwmril
UW Research Initiated andFunded by Wisconsin Dept. Of
AgricultureConcerns raised by citizens strayvoltage advisory board
Transient voltageTransient voltage
"Objectionable currents
Magnetic fields
Other phenomena beyond "classicalstray voltage"
UW Research Team1. D. Reinemann - UW Biological Systems Eng
2. L. Stetson - USDA-ARS
3. Steven D. LeMire, UW Biostatistics
4. N. Laughlin UW Psychology, Animal Behavior
5. J. P. Reilly - Johns Hopkins APL, Electro-pathology5. J. P. Reilly - Johns Hopkins APL, Electro-pathology
6. S. McGuirk - UW Vet School, Physiology
7. E. Nordheim - UW Statistics
8. L. Armentano - UW Dairy Science
9. M. Rasmusssen, Danish Inst. Agricultural Science
10. Milo C. Wiltbank, UW-Dairy Science
11. Lewis G. Sheffield, UW-Dairy Science
Sensitivity (BehavioralResponse) Tests, 500 Cows
Muzzle to hooves
60 Hz, 1, 5, 9, 10 cycles
500 Hz, 1 cycle500 Hz, 1 cycle
6000 Hz, 1, 9, 100 cycles
50,000 Hz, 1, 5, 833 cycles, sine, 1/2sine, square
Milking machine exposure
Sensitivity to magnetic fields
Volts (Zero to Peak)Muzzle - Hoof
Volts (Zero to Peak)Hoof - Hoof
Approximate 60 Hz Steady State Behavioral Response Distribution
2 3 4 5 7
Volts (Zero to Peak, measured across 500 Ohm resistor)
J.P. REILLYBIO-
ELECTRICITY1998
Behavioral response for 5% most sensitive cows, sine wavesmuzzle to hooves exposure
100
1,000
10,000
Vo
lta
ge
(Ze
roto
Pe
ak)
50
0O
hm
Co
wC
on
tact
1 cycle Biphasic
1 cycle Monophasic
Multi CycleFencers
1
10
0.1 1 10 100 1000 10000
Phase Duration (microseconds) = time between zero crossings
Vo
lta
ge
(Ze
roto
Pe
ak)
50
0O
hm
Co
wC
on
tact
Dairy Cow Response to MultipleFrequency WaveformsFrequency Waveforms
Douglas J. Reinemann, Ph.D.
Paul D. Thompson, PhD
Charles Forster, Mr. Pulsar
University of Wisconsin- Madison
Single Frequency Waveforms
1.5
2.0
2.5
3.0
Se
ns
itiv
ity
Ra
tio
0.0
0.5
1.0
1.5
0 2 4 6 8
Time (ms)
Se
ns
itiv
ity
Ra
tio
Average Response to60 Hz = 11 mA
Multiple Frequency Waveforms
1.0
2.0
3.0
4.0
5.0 Response tocombined 60Hz +
Narrow pulse sameas for Narrow pulse
alone
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
0 2 4 6 8 10 12 14 16 18
Time (ms)
When 60 Hz peak isbelow 60 Hzresponse level
Multiple Frequency Waveforms
1
1
2
2
When peak of Pulseis below Responselevel for the pulsealone
-2
-2
-1
-1
0
0 2 4 6 8 10 12 14 16 18
Time (ms)
Response levelfor 60 Hz peak isthe same as for60 Hz alone.
1
1.5
2
2.5
Response toPulse + Ring notdifferent fromPulse alone
-1
-0.5
0
0.5
2000 2100 2200 2300 2400 2500 2600
Sensitivity to combined frequencycomponents
Combining waveforms did not changesensitivity to individual waveformsCombining waveforms did not changesensitivity to individual waveforms
UW Aversion Tests (120 Cows)
1 cycle 60 Hz
Water bowl tofloor
1 per second
3 week
Exposure method
Control
Reaction level
1.5 timereaction level3 week
exposure
1 cycle 6000 Hz
Water bowl tofloor
1 per second
3 day exposure
reaction level
100
120
140D
aily
Wa
ter
(L)
Control P 7-13mA P+ 8-14mA P++ 9-17mA P*11-20mA
60
80
-7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7
Days
Da
ily
Wa
ter
(L)
1
1.05
1.1
Fra
cti
on
of
Da
ily
Wa
ter
Co
ns
um
ed
Control R(7-13mA) R+(8-14mA)
R++(9-17mA) R*(11-20mA)
0.8
0.85
0.9
0.95
Pre Test Post
Fra
cti
on
of
Da
ily
Wa
ter
Co
ns
um
ed
21 Day Average Water
Single Cycle 60 Hz AversionChange in 3 Day Average Water Consumption
-2
0
2
4
6
Ga
llo
ns
/C
ow
/D
ay
-10
-8
-6
-4
-2
R 1.2 R 1.5 R
Exposure Level
Ga
llo
ns
/C
ow
/D
ay
Single Cycle 60 Hz AversionHours delay to drink first gallon of water
15
20
25
30
Ho
urs
0
5
10
15
Control 1.2 R 1.5 R
Exposure Level
Ho
urs
Behavioral response for 5% most sensitive cows, sine wavesmuzzle to hooves exposure
100
1,000
10,000
Vo
lta
ge
(Ze
roto
Pe
ak)
50
0O
hm
Co
wC
on
tact
1 cycle Biphasic
1 cycle Monophasic
Multi CycleFencers
1
10
0.1 1 10 100 1000 10000
Phase Duration (microseconds) = time between zero crossings
Vo
lta
ge
(Ze
roto
Pe
ak)
50
0O
hm
Co
wC
on
tact
Continuous Vs. IntermittentExposure
Hrs Delay Ave Diff. P-value Significant
Control vs.One shock
-0.4 .14 NoOne shock
Control vs.Intermittent
-0.4 .21 No
Control vs.Continuous
+5.6
AgroParisTech Roussel(2007)
avoidance test threshold level
steps of 0.3 Volts up to 5 Volts applied to feedingcup
2.3V, % total feed and the time spent eating in 2.3V, % total feed and the time spent eating inthe electrified feeder decreased
> 3 Volts heifers changed more quickly to the non-electrified feeder
> 2 Volts more muzzle-grooming and head shaking
2.3V appeared to be the threshold at whichavoidance behaviour starts
Effects of Stray Voltage on Behaviour, Stress
Physiology and Production Parameters of Sheep and
Dairy Cows.Short and mid-term effects
117
AgroParisTechC. DUVAUX-PONTER, F. GALLOUIN, S. ROUSSEL,
K. RIGALMA (PhD since 2006)Experimental farm of AgroParisTech
M. SAADE, D. TRISTANT and the farm staffTrainees and assistants
A. BARRIER, A.-C. BURGE, M. CARRIERE, C. CHARLES, M. ENNIFAR, C. EON, A.MALHERBE, P. MALSERT, A. OLIVEIRA, P. PIQUEREL, C. SCHREINER
RTE - EDFF. DESCHAMPS, L. DEVEAUX, F. FORTIN, J.-P. GERNEZ, T. LOUYOT
Percentage of feed eaten in the electrified feeder
n = 20 (CONT heifers are used to control day effect)
Reaction threshold in heifers (experiment 3)
60
80
100NS
*** ***NS NS NS NS NS NS
*** ***** ***
********
Reaction threshold = 2.3 V
118Voltage (V) applied
0
20
40
60
0 0.3 0.6 1 1.3 1.6 2 2.3 2.6 3 3.3 3.6 4 4.3 4.6 5
%
Latency to switch to the non-electrified feeder(seconds)
Reaction threshold in heifers (experiment 3)
Reaction threshold = 2.3 V
80
100 ******
NS NS NS NS NS NS
****** ******** **
NS
119
Voltage applied (V)
0
20
40
60
80
0 0.3 0.6 1 1.3 1.6 2 2.3 2.6 3 3.3 3.6 4 4.3 4.6 5
seco
nds
*** ******
n = 20 (CONT heifers are used to control day effect)
Percentage of heifers performing at least one abrupthead movement during the 2-min test
CONT n = 20
20
25
30 NS * *
Reaction threshold in heifers (experiment 3)
120
VOLT n = 20
0
5
10
15
20
0.3 to 1.6 V 2.0 to 3.3 V 3.6 to 5.0 V
%
Rigalma (2007) 3-week 3.3 Voltexposure metallic feeders
continuous (C) or unpredictable (U)
20 nave (NH)and 20 experienced (EH) heifers
unpredictable exposure
more time eating in the electrified feeder
more abrupt head movements and more muzzle-groomingmore abrupt head movements and more muzzle-groomingbehaviors
than those in the continuous exposure group
No behavioral differences between NH and EH
NH higher cortisol concentrations on first day
NHC ate more and changed feeder quicker than theNHUexposure group
Unpredictable exposure had more difficulty in adaptingand that past-experience seemed to reduce the response.
Rigalma (2008)
unpredictable exposuremay not offer sufficienttime to the heifers totime to the heifers tolearn how to adapt.
Minnesota Science AdvisorsEarth Current Study
Endocrine And Immune FunctionResponse Of Dairy Cows To Electrical
Current Exposure
Minnesota / WisconsinOpinion Survey
Conducted by USDA AgriculturalStatistics service
Random sample of 1300 farms
Electrical exposures listed in
Random sample of 1300 farms
Electrical exposures listed inbottom 1/3 of 26 animal health andproduction concerns
Minnesota Field Study
60 Hz voltage below perception onall farms
Motor starts below perception
High frequency events belowHigh frequency events belowperception
Magnetic fields below level ofconcern
Widespread problems with fencersand trainers
Minnesota Field Study
Step Potential (Mainly from localsources)
Barnyard 1 - 50 mV
Field 0 - 11 mVField 0 - 11 mV
Stall 1 - 30 mV average (3-150 mVMaximum)
Further study of earth currents fromdistant sources cannot be justified
Physiological effects of small steppotentials being investigated
Magnetic FieldMeasurements on Wisconsin
Dairy FarmsDasho ASAE 963071
Measurements on 106 Farms
Levels in Barns Lower Than inLevels in Barns Lower Than inResidence
No Relationship with Cow ContactVoltage
Not a likely source of problems
Minnesota Science AdvisorsGround Current Study:
The Hypothesis
Continuous contact of confined cowsto low level (sub perception)voltage/current may produce,voltage/current may produce,
Electric fields inside the cow atlevels high enough to produceBiological effects
Change in cow activity in response tocurrent exposure
10
20
5m
inc
ha
ng
ein
ac
tivit
y
-20
-10
0
0.5 R 0.75 R 1.0 R 1.5 R
Treatment Level
5m
inc
ha
ng
ein
ac
tivit
y
24
Co
rtis
olco
nce
ntr
atio
n(n
g/m
L)
No increase in Cortisol for CurrentExposure below behavioral response
-4-2
0
0.5 R 0.75 R 1 R 1.5 R
Co
rtis
olco
nce
ntr
atio
n(n
g/m
L)
40
50
Paired T-testp = 0.0001
No Cortisol response for current exposureBig Cortisol response for hoof trimming
010
20
30
Cort
isol(n
g/m
l)
Before
Current
After
Current
1.5 R
Before
Hoof
Trimming
After
Hoof
Trimming
Treatments applied duringmilking
Control
Hoof-hoof voltage exposure belowsensitivity threshold
Milking machine induced stressMilking machine induced stress
Measures
Stepping
Average and peak milk flow during milking
Pounds of milk yield
Milking time
Milk Yield (kg) 1.19+ 0.13
0.24 + 0.15
PulsationFailure
1 mA currentexposure
No response to currentSome response for broken milking
machine
Average Flow Rate(kg/min)
0.24 + 0.15
Maximum Flow Rate(kg/min)
0.29 + 0.04
Activity (weight shifts/ milking)
-5.84 *** -1.28
Strip Yield (% ofquarters > 10 ml)
-0.10 0.09
Immune response tocontinuous low level current
exposure
1 mA Exposure Front - Rear Hoof,
10 Minutes off/on for 2 weeks10 Minutes off/on for 2 weeks
No change in
Immune function response
Time and pattern of laying
Time to re-enter stall after milking
Immune Tests
Blood samples twice weekly
lymphocyte blastogenesis
Dose responses to standard mitogens,
S. aureus, Phytohemagglutinin, PokeweedS. aureus, Phytohemagglutinin, PokeweedMitogen and Concanavalin A
Chemiluminescence measure of Oxidativeburst
Interluken I
Cortisol
Conclusions
No difference between control andtreatment cows for any of the 3 mainresponse variables
Statistically significant difference for 1 ofStatistically significant difference for 1 of10 of the secondary response variables
But did not appear to be consistent withother observations
Collectively, these results suggest thatexposure to 1 ma of current for two weekshad no significant effect on the immunefunction of dairy cattle.
WI Immune II ResultsMost measures were not affectedA small subset of immune system regulators
showed possible changes:Could be Type I errors, due to the large
number of hypotheses tested.number of hypotheses tested.The magnitude of effect was relatively small,
compared to that often observed in theliterature in response to major immunesystem challenges
Immune function conclusionsSmall subset of immune systemregulators showed possible changes
most disease processes affect a widerspectrum of regulators
Type I errors, large number tested (?)
Any possible impacts of electricalAny possible impacts of electricalexposure on immune function healthand disease are of relatively small anddifficult to detect
Collectively, these results suggestthat exposure to 1 ma of current fortwo weeks had no significant effect onthe immune function of dairy cattle
Findings of the MinnesotaScience Advisors
We have not found credible scientific
evidence to verify the specific claim that
currents in the earth or associatedcurrents in the earth or associated
electrical parameters such as voltages,
magnetic fields and electric fields, are
causes of poor health and milk
production in dairy herds
Wisconsin Field Study
Stray Voltage Analysis Team (SVAT)Public Service Commission of Wisconsin(PSCW)
Wisconsin Department of AgricultureWisconsin Department of AgricultureTrade and Consumer Protection(WDATCP)
> 360 Investigations 88-98
Electric Utilities8000 First-Time Farm Investigations93-2007
PSCW Field Study8000+ Farms
No Correlation Between
Milk production or Somatic CellCount andCount and
Primary NEV
Secondary NEV
Cow Contact Voltage
Ground Rod Current
15000
20000
25000
30000
35000
Milk
Pro
du
cti
on
(RH
A)
0
5000
10000
15000
0 50 100 150 200 250 300
Ground Current (mA)
Milk
Pro
du
cti
on
(RH
A)
R2 = 0.00p = 0.97
1000
10000
SC
C
10
100
0 50 100 150 200 250 300
Ground Current (mA)R2 = 0.02P = 0.11
15,000
20,000
25,000
30,000
Mil
kP
rod
ucti
on
(RH
AL
b/c
os)
5,000
10,000
15,000
0.00 0.20 0.40 0.60 0.80 1.00
Cow Contact Voltage
Mil
kP
rod
ucti
on
(RH
AL
b/c
os)
R2 = 0.01p = 0.29
800
1,000
1,200
1,400
1,600
SC
C(x
1000)
0
200
400
600
0.00 0.20 0.40 0.60 0.80 1.00
Cow Contact Voltage
SC
C(x
1000)
R2 = 0.03p = 0.11
15000
20000
25000
30000
Mil
kP
rod
ucti
on
(RH
AL
b/C
ow
)
0
5000
10000
0 0.5 1 1.5 2 2.5 3
Primary Neutral to Earth Voltage
Mil
kP
rod
ucti
on
(RH
AL
b/C
ow
)
R2 = 0.01p = 0.33
800
1000
1200
1400
1600
SC
C
0
200
400
600
0 0.5 1 1.5 2 2.5 3
Primary Neutral to Earth VoltageR2 = 0.00p = 0.75
Average Monthly Milk Production in Wisconsin
43
44
45
46
47
48
Lb
/Co
w/D
ay
38
39
40
41
42
43
Jan-
95
Mar
-95
May
-95
Jul-9
5
Sep-
95
Nov-95
Jan-
96
Mar
-96
May
-96
Jul-9
6
Sep-
96
Nov-96
Jan-
97
Mar
-97
May
-97
From Wisconsin Ag Statistics 97
Lb
/Co
w/D
ay
Monthly Average SCC from Upper Midwest
Federal Orders #68 and #30, and IOU data
350
400
450
SC
C
FO 68 UMW
FO 30 CHI
iou
200
250
300
Jan-9
3
Ap
r-9
3
Jul-9
3
Oct-
93
Jan-9
4
Ap
r-9
4
Jul-9
4
Oct-
94
Jan-9
5
Ap
r-9
5
Jul-9
5
Oct-
95
Jan-9
6
Ap
r-9
6
Jul-9
6
Oct-
96
SC
C
r = 0.59
Review of Sensitivities ofOther Species
Swine
greater than 3.0 mA was needed to affect drinkingtime and 4.0 mA to affect consumption.
feed intake, daily gain were lower in the 5 V groupthan 2V and controlthan 2V and control
up to 8 V does not impair the welfare, reproductiveperformance, or health of sows and suckling pigs
Up to 8 V no significant effects on feeding,drinking, sitting or lying activities. slight increase inrooting bouts 5-8V head butting 2-5V
Review of Sensitivities ofOther Species
Sheep
Above 5.5 V ewes tended to spendmore time eating and to eat moremore time eating and to eat morefrom the non-electrified feeder
At 5V and upwards, lambs spentless time eating in the electrifiedfeeder
Review of Sensitivities ofOther Species
Poultry
0 to 9 volts did not impair egg production
electrical resistance of hens much higherthan cattle and pigsthan cattle and pigs
as high as 18 V had no effect on hens'production and behavior (2)
stray voltage present in many breederhouses may contribute to floor eggs
factors other than up to 9 V may havebeen causing a floor egg problem.
Recommended