See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/275578859 Behavioral Studies of Dairy Cattle Sensitivity to Electrical Currents Article in Transactions of the ASAE · January 1983 DOI: 10.13031/2013.34160 CITATIONS READS 27 87 4 authors, including: Richard John Norell J. Bruce Overmier University of Idaho University of Minnesota Twin Cities 10 PUBLICATIONS 92 CITATIONS 184 PUBLICATIONS 5,085 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Just finished a review paper on Learned Helplessness. View project All content following this page was uploaded by J. Bruce Overmier on 16 November 2015. The user has requested enhancement of the downloaded file. SEE PROFILE Behavioral Studies of Dairy Cattle Sensitivity to Electrical Currents R. J. Norell, R. J. Gustafson, R. D. Appleman, J. B. Overmier MEMBER ASAE ABSTRACT LECTRICAL resistance data were collected for eight pathways through dairy cows. Significant variation in resistance was found between pathways through individual cows and between cows. The mean path resistances ranged from 359 ohms for a mouth-all hooves pathway to 738 ohms for a front-rear hooves pathway. The distribution for the mouth-all hooves pathway showed 25% of the population below 302 ohms and 75% below 441 ohms. Three experiments assessing animal sensitivity to current based on behavioral indicators were performed. No suppression of a learned response to obtain food was found up to 6.0 mA front-rear hooves shock. However, muzzle-all hooves shocks as low as 1.0 mA suppressed plate pressing behavior. A specific avoidance response to a mouth-all hooves shock was exhibited 13.8% of the time at 1.0 mA and 92.3% at 4.0 mA, while a learned escape response to a front-rear hooves shock above a normal activity level occurred between 2.0 and 3.0 mA. E INTRODUCTION Awareness of the presence of stray voltage in livestock facilities has risen rapidly in the last few years. However, very limited data are available on the electrical characteristics and current sensitivity of farm animals. The first component of this paper reports data collected on the resistance to alternating current (ac, 60 Hz) for likely pathways through dairy cows. The second component reports results of three experiments measuring sensitivity to electrical currents based on behavioral indicators. The specific objectives of the resistance measurement component of this study were to: (a) measure resistance of eight pathways through dairy cows, (b) determine correlations bewteen cow attributes (body weight, wither height, body length and age) and measured pathway resistances, and (c) estimate the contribution of the hooves to the total path resistance. The objective of the current sensitivity component of this study was to study cow response to graduated levels Article was submitted for publication in January, 1983; reviewed and approved for publication by the Electric Power and Processing Div. of ASAE, 1983. Presented as ASAE Paper No. 82-3530. Published as Paper No. 13,214 of the scientific journal series of the Minnesota Agricultural Experiment Station. The authors are: R. J. NORELL, Assistant Professor and Extension Dairyman, Animal Science Dept., University of Idaho, Idaho Falls; R. J. GUSTAFSON, Associate Professor, Agricultural Engineering Dept., and R. D. APPLEMAN, Professor and Extension Dairyman, Animal Science Dept., J. B. OVERMIER, Professor, Psychology, University of Minnesota, St. Paul. Acknowledgment: The authors wish to acknowledge support received from the National Rural Electric Cooperative Assn. for stray voltage research at the University of Minnesota. 1506 of mouth-all hooves and front-rear hooves currents. The criteria for assessing cow response were behavioral indices. In one experiment, shocks were an aversive stimulus to a learned food acquiring response. The indicator was a partial suppression or slowing down of the learned response. In a second experimental approach, response functions to random front-rear hooves and mouth-all hooves shocks were determined. The shock were random in that the initiation of the shock was not under the cow's control as in experiment one. The response indices were the displaying of a learned escape to a front-hooves shock and a shock elicited mouth opening due to a mouth-all hooves shock. REVIEW OF LITERATURE Resistance variability between cows and pathways is clearly evident from the available data. Phillips and Parkinson (1963), Craine et al. (1970), Woolford (1972), Whittlestone et al. (1975) and Lefcourt (1982) reported average resistances in the range of 250 to 1200 ohms for various pathways. A combination of differences in method of measurement, contact resistances, and actual path resistances likely explain the five-fold or more differences in resistances between specific pathways. Altered animal behavior and milking characteristics, increased incidence of mastitis, and lowered milk production have been reported as a consequence of electric shocks (Fairbank and Craine, 1978; Cloud et al., 1981; Surbrook and Reese, 1981; Williams, 1981). The relationship between reported cow responses and shock intensity are poorly understood and have received limited study. The majority of the existing research involved the application of shocks during the act of milking. Shocks from the milking machine had a minimal effect on milk flow characteristics or milking times (Phillips and Parkinson, 1963; Woolford and Copeland, 1969; and Woolford, 1972). However, in the latter two studies, cattle were reluctant to enter the parlor and exhibited signs of annoyance such as increased hoof movement. Woolford (1972) concluded that voltage gradients along the parlor floor or between the parlor pipework and floor may be more bothersome to the cow than shocks from the milking machine. Whittlestone et al. (1975) obtained threshold responses for four animal pathways likely to be exposed to shocks in the milking parlor. The body pathways studied were: one teat-all hooves; all teats-all hooves; rump-all hooves; and chest-all hooves. The threshold response was a change in preference of a paddle pressed for a grain reward. One paddle turned the current "on" and the other turned it "off. Average threshold voltages and currents were: teat-all hooves, 6.2 V/7.1 mA; all tests-all hooves, 7.8 V/5.6 mA; rump-all hooves, 4.3 V/6.1 mA; and chest-all hooves, 4.0 V/4.0 mA. © 1983 American Society of Agricultural Engineers 0001-2351/83/2605-1506$02.00 TRANSACTIONS of the ASAE—1983 VOLTMETER I STEP DOWN ISOLATING TRANSFORMER STEP DOWN AUTOTRANSFORMER r ~ 1 TABLE 1. AVERAGE PATHWAY RESISTANCE MEASURED UNDER DRY AND WET HOOF-GRID CONTACT CONDITIONS, OUTLIER REMOVED (n = 10 JERSEYS). Condition X SD X SD 1562 1265 621 (470) (378) (191) 1479 1167 647 (275) (321) (173) FIXED RESISTANCE R= 79 kXi Fig. 1—Electrical resistance measurement circuit. Lefcourt (1982) studied cow response to graded shock increments applied to a front-rear leg pathway. Electrodes were attached above one front and one rear hoof. Average currents and voltages corresponding to a milk and strong response were: milk, 0.8 V/2.5 mA; strong, 1.1 V/3.5 mA. Henke et al. (1982) studied the response of four cows to udder-hooves shock. An electrode was attached at the back of the udder beneath the tail while the animal stood on perforated steel. Behavioral responses occurred at currents of between 2 mA and 4 mA. Endocrine responses were poorly correlated with shock intensity. RESISTANCE MEASUREMENTS Equipment and Procedure The floor of a wood-frame tie stall was adapted to make separate contacts with front and rear hooves. Two expanded metal grates (0.8 m x 0.9 m) isolated by a section of cow mat and rubber matting were placed on the stall floor. Other contact points were established by (a) a steel bit in the cow's mouth and (b) an aluminum foil-lined teat cup inflation (plus EKG paste) attached to the left front teat. Eight different circuits or pathways through the cow were defined using these connections. The electrical circuit used for resistance measurements (Fig. 1) was designed to maintain a constant current. A fixed impedance source as described by Masterton and Campbell (1967) was used. With this system, normal variation in cow resistance was expected to produce less than a 1.5% change in current level. Digital volumeters were used to measure voltage across the fixed resistor and cow pathway. The current flow through the circuit was adjusted to 0.1 mA. Calculated cow pathway resistance was recorded as the average of five determinations. Standard errors of the mean were small for the five determinations, usually 5-10 ohms. Results Experiment 1R—Dry and Wet Hooves Comparisons The objective of this experiment was to compare the influence of wet versus dry hooves on pathway resistance. The hypothesis was that a wet hoof would lower the hoofgrid contact resistance and thereby decrease the overall pathway resistance. Data were collected in two different sessions. In one session, the underside of the hoof was brushed to remove dry manure and bedding. This was the dry hoof condition. In the other session, the hooves were carefully washed and the metal dampened before resistance measurement. The grids and hooves were sprayed with water between determinations to maintain the wet hoof conditions. 1983—TRANSACTIONS of the ASAE Mean difference (dry-wet) Standard error 83 98 -26 101 95 16 , Front-rear hooves Mouth-front hooves Mouth-rear hooves VOLTMETER 2 Wet Dry -V\A/ The resistance of a front-rear hooves, mouth-front hooves, and mouth-rear hooves pathway were determined, under wet and dry hoof conditions, on eleven Jersey cows. Statistical comparisons were paired t-tests of pathway resistance measured under wet and dry hoof conditions. Upon analyzing different pairs (dry-wet for an individual cow), it was found that data for one cow accounted for the large inequality in variance between hoof conditions. The reasons for the greater dry hoof resistance of this outlier cow are not known. Data from this cow indicated pathway resistance may be considerably increased under dry hoof conditions. Deleting these data from the analyses nearly halved the pathway resistance variance between cows under the dry hoof measurement conditions. Average pathway resistances and differences between dry and wet conditions for the reduced data set are in Table 1. Variances in pathway resistance between measurement conditions were not significantly different in the reduced data set. Mean differences between wet and dry hoof resistances on the expanded metal grids were also not significant. Experiment 2R—Resistance of Eight Pathways The electrical resistance of eight defined cow pathways were measured on twenty-eight Holstein cows. Resistance determinations were made under the "wet hoof-grid" contact conditions as defined for Experiment 1R. Pathway resistances were compared with a randomized block statistical design. Cows were the blocks and pathways were the treatments. A log 10 transformation was used to make the pathway resistance data more normal and to reduce variance inequality. Mean pathway resistances and their associated standard deviations are presented in Table 2. Ranking the measured pathways from lowest to highest resistance yields: (a) mouth-all hooves; (b) mouth-teat; (c) mouthrear hooves; (d) teat-all hooves; (e) mouth-front hooves; (f) teat-rear hooves; (g) front-rear hooves; and (h) teatfront hooves. TABLE 2. MEAN RESISTANCES AND STANDARD DEVIATIONS FOR THE EIGHT MEASURED COW PATHWAYS (n = 28 HOLSTEINS). Log 10 ohms Pathway X SD Front-rear hooves Mouth-front hooves Mouth-rear hooves Mouth-all hooves Mouth-teat Teat-front hooves Teat-rear hooves Teat-all hooves 2.868 2.789 2.686 2.555 2.656 2.944 2.861 2.778 .130 .109 .129 .106 .149 .133 .137 .141 Geometric mean, ohms 738 615 485 359 452 877 726 600 1507 TABLE 3. RESISTANCE DISTRIBUTIONS BY BODY PATHWAY (n = 28 HOLSTEINS). TABLE 4. CONTRIBUTION OF THE HOOF AND HOCK TO THE TOTAL PATHWAY RESISTANCE (n • 9 HOLSTEINS). vleasuremenl ' (ohms) Percentiles* 10% Front-rear hooves Mouth-front hooves Mouth-rear hooves Mouth-all hooves Mouth-teat Teat-front hooves Teat-reat hooves Teat-all hooves 25% 50% A 75% 90% Cow pathway Front-rear hooves 713 Mouth-front hooves Mouth-rear hooves Mouth-all hooves 652 596 437 496 590 734 875 1152 420 345 244 541 398 302 624 475 361 715 572 441 851 776 525 294 354 433 597 713 593 503 402 679 594 455 874 710 594 1048 1508 1203 894 767 Significant differences existed between the pathway means. Constrasts were used to compare pathway resistances including: two versus four hooves; front versus rear hooves; and mouth versus the teat. Pathway resistances including four hooves were significantly lower than those including two hooves. The resistance of pathways including front hooves only were greater than those including rear hooves only. Resistances of both pathways including mouth-hoof combinations were lower the those including teat-hoof combinations. The mouthteat pathway was significantly lower in resistance than the teat-hoof pathway combinations. The front-rear hooves pathway resistance was larger than the mouthhoof combinations but not the teat-hoof combinations. Variability between cows also exists for a given pathway. Selected percentile limits (10%, 25%, 50%, 75%, and 90%) for each pathway are displayed in Table 3. A percentile defines the percent of the population below the listed limit. These data are useful in illustrating differences in current flow between cows due to an applied voltage. For example, assuming a mouthall hooves pathway, 10% = 244 ohms and Rgo% = 525 ohms. In this case, 10% of the cattle exposed to a 1.0 V mouthall hooves shock would receive a 4.0 mA or greater shock while 90% of the cattle would receive a 1.9 mA or greater shock. These data demonstrate a two-fold difference in resistance and resulting current flow within the middle 80% of the population. Simple correlations between individual pathway resistances and indices of cow size and age were calculated. Selected indices of cow were: body weight (kg), heart girth (cm), wither height (cm), body length (withers to pins, cm) and age (mo). There were seven cows each in their first through fourth lactations. Correlations between body measurements and pathway resistances were inconclusive. Pathway resistances were not correlated with body weight, heart girth, and body length. Wither height was significantly correlated with teat-front hooves (r = 0.38) and teat-all hooves (r = 0.37) resistance. Age was negatively correlated (r = -0.45) with the resistance of the mouthrear hooves and mouth-all hooves pathways. The repeatability of this age-pathways resistance correlation should be examined. Numbers were relatively small within age categories. 1508 B SD Difference? (A-B) Standard error of difference X SD 327 (97) 386* 105 292 265 197 (52) (31) (16) 360* 331* 240* 49 64 34 * (p < . 0 1 , paired t-test) ' Measurement A included the hooves and hocks in the cow pathway. Measurement B was the pathway terminating at EKG electrodes attached above the hock on each hoof. + The difference between measurements A and B was assumed to be the hoof and hock contribution to total pathway resistance. 953 * The percentiles are the percent of the measured resistances below the reported limit. R X ill! Pathway Experiment 3R—Hoof and Hock Resistance The objective of this trail was to estimate the contribution of the hoof and hock to the total pathway resistance. The hoof contributes to the total pathway by its internal resistance and by the hoof-grid contact resistance. Since direct measure was not possible, an estimate was derived by measuring two pathways through the cow. One path involved the mouth-all hooves pathway. The second path involved the mouth to EKG electrodes plus paste applied above the hocks. This configuration removed the hooves from the circuit. The difference between the two paths provides an estimate of the resistance of the four hooves in parallel. This estimate is only an approximation of hoof resistance because: (a) the electrode alters the current flow pattern through the leg and (b) the electrode-skin contact has an associated contact resistance which is not a part of the internal body resistance. Data were measured (with and without the hooves) for four pathways using nine Holstein cows. Average pathway resistances, with and without hooves, are displayed in Table 4. Total pathway resistance was decreased by approximately 55% for all four measured circuits when the hooves were not included. BEHAVIORAL EXPERIMENTS Experiment IB—Aversion to Learned Response Equipment and Procedure A specially constructed the stall was used for this experiment. The stall base contained two separate basins (0.8 m x 0.9 m) with expanded metal floors for contact with the front and rear hooves. Water was added to the basins to assure a stable hoof-grid contact. STEP DOWN AUTOTRANSFORMER 120 V STEP UP (112) TRANSFORMER FIXED RESISTANCE -AAA, RF = 28 k & SHOCK CONTROL RELAY CONTACT 1| Re IHTTH FRONT AND REAR GRIDS PRESS PLATE SWITCH * 24 V * IMPULSE COUNTER AND RECORDER SHOCK CONTROL AND TIMER Fig. 2—Electrical circuitry for Experiment IB. TRANSACTIONS of the ASAE—1983 T A B L E 5. P L A T E P R E S S I N G S U P P R E S S I O N T H R E S H O L D S The schematic of the electrical circuit is illustrated in DUE TO MUZZLE-ALL HOOVES SHOCKS. Fig. 2. The application of the shock was contingent upon a muzzle plate press. The first treatment, front-rear Session hooves shocks, was initiated by a microswitch located 1 2 3 inside the press plate. The second treatment, muzzle-all Cow A* D* A* D* A* D* hooves shocks, was initiated by touching the metal plate. milliamps In other words, the plate was "live" and the cow completed the circuit by touching it. The maximum 952 1.0 3.5 1.0 899 1.0 1.0 2.0 deliverable current to the cow from this source was 6.0 967 2.0 2.0 2.0 mA. Current flows were within 2% of the desired value ND1" 4.5 968 ND1" when a cow was placed in the circuit. 1013 4.5 4.0 4.5 1.0 1.0 3.0 A metal press plate and the grain delivery system was 1019 positioned in front of the cow. Six Holsteins were trained * S h o c k series, A stands for ascending and D for descending series. to press the plate by the method of sequential ' N D = n o t d e t e r m i n e d , an ascending series of 0 . 2 5 m A i n c r e m e n t s u p t o 4.0 m A was p r e s e n t e d . approximation. Initially, the experimenter manually + NM = n o t m e a s u r e d , cow w o u l d n o t stabilize h e r plate pressing activated the feeder for head movements close to the behavior. press plate. Secondly, grain rewards were given only when the cow's muzzle was in front of the press plate. The cattle would begin plate pressing shortly after they avoidance of the "live" metal plate. The cow would make had reached the second stage of training. Grain rewards several touch contacts before pressing the plate with were delivered upon each plate press for three sessions sufficient force to activate the plate press recorder. Once (each 0.5 h duration). The grain rewards were 70 grams started, plate pressing was conducted at the normal rate. of a mixture of beet pulp (75%) and shelled corn (25%). The interval between grain rewards was lengthened due The number of plate presses required to receive grain to these touch avoidances. The shock intensities which suppressed plate pressing rewards was gradually increased (in five-press increments) until stable rates were achieved at 30 presses behavior are shown in Table 5. Suppression currents per reward. Based on Azrin and Holz (1959), the plate varied between cows and sessions. Four out of six cows press contingent shocks in this study were expected to were initially suppressed by 1.0 to 2.0 mA shocks. Higher lengthen the interval between grain rewards. A grain shock intensities were required to suppress plate pressing reward interval was the time interval starting at the behavior during later sessions. The reasons for the initiation of plate pressing and ending at the start of adaptation by these cows by 1.0 to 2.0 mA are not plate pressing for the next reward. The lengthening of known. Shocks of 4 to 4.5 mA were required to initially this interval is a slowing down or partial suppression of suppress plate pressing behavior of one other cow. Response suppression then continued for two consecutive the learned food acquiring response. 0.5 mA decrements. A one-tailed 95% confidence limit for the mean of A definitive low suppression threshold cannot be three grain reward intervals was the response threshold measure. Data used to calculate the 95% one-tailed limit derived from these data. The touch avoidances were were the mean grain reward interval and standard occurring over a broad range of shocks (1.0 to 4.5 mA). deviation from the last three control plate pressing days. Suppression currents were generally between 3.0 and 4.5 Approximately 150 grain reward intervals were measured mA on the second session (4 to 6 cows) and third session (5 of 5 cows). on these control days for each cow. The treatments were front-rear hooves and muzzle-all hooves shocks. Three separated experimental sessions Experiment 2B—Learned Escape Responses, were conducted for each treatment. During a session, a Front-Rear Hooves Shock cow was alloted four hundred fifty no-shock plate presses Equipment and Procedure A 1.5 m high wall was built around the stall described to "warm up". An ascending series of shocks (0.5 mA in Experiment IB for use in this trial. Electrical increments) was then presented. Cattle were exposed to each shock intensity for three grain reward intervals until connections to the animal were the two metal grids in the 95% confidence limit was exceeded. If the limit was water-filled basins. A manually operated switch, exceeded, the cow's plate pressing behavior was controlled by an observer, initiated the shock. A second considered suppressed. A decending series followed (0.5 operator adjusted the electrical current level, such that mA decrements) until the mean of three grain reward the animal observer was unaware of the current level. Seven Holstein cows were exposed to fifty training intervals was within the confidence limit. shocks during one session. A 5.0 mA front-rear hooves pulsating (repeated on and off at approximately 60 cycles Results per minute) shock was used. The maximum training Front-rear hooves shocks up to the 6 mA limit did not shock duration was thirty seconds. The shocks were suppress plate pressing behavior. Apparently, higher terminated early when the cow picked up a front hoof. shock intensities through this body pathway are required The interval between shocks was variable, ranging from to influence plate pressing behavior. Subjective signs of thirty to ninety seconds. All seven cows were picking up a annoyance such as hoof movement during plate pressing front hoof on 90 to 100% of the trials at the conclusion of were occasionally observed. However, the observed hoof the training. The learned escape response was expressed movement occurred too infrequently to correlate with in less than 10 seconds from the shock onset. shock intensity. During a second session, twenty-four hours later, the Plate pressing behavior was suppressed by muzzle-all cattle were exposed to twenty 5.0 mA "warm-up" shocks hooves shocks. The typical response was a touch followed by a series of sixty shocks. Front hoof pickups 1983—TRANSACTIONS of the ASAE 1509 T A B L E 6. O B S E R V E D P E R C E N T ESCAPES BY C U R R E N T I N T E N S I T Y F O R F R O N T - R E A R H O O V E S SHOCKS (n = 6 0 ) . Current, m A 0.0 1.0 2.0 3.0 4.0 5.0 Escapes, 18.3 23.2 25.0 43.3 71.7 96.7 Difference, ' SE,% 5.0 1.7 18.3* 28.4** 25.0** 6.8 6.8 8.0 8.5 6.5 9 5 % CONFIDENCE INTERVAL * (p<0.05) **(p<0.01) occurred on 90 to 100% of the warm-up trials. The shock series, which followed the warm-up trials, included six current intensities (0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 mA) which were randomly assigned within ten blocks of time. Two cows were exposed to only five replications of each intensity. The pulsating shocks were presented for a maximum duration of 10 seconds. A front hoof pickup terminated the shock trial early. Response rates (summed across cows) were compared between adjacent 1.0 mA pairs with a chi square test of proportion in paried samples. Results The observed escape frequency (in percent) for each current intensity is shown in Table 6. The observed twenty percent escape rate at the lower three intensity is assumed to be random front hoof movement rather than an attempt to escape the shock. This was verified by preliminary study, where under no shock conditions ten cows were observed to pick up a front hoof on twenty-two percent of the observation trials (n = 50 per cow). Significant increases in escape percentage occurred for each 1.0 mA increment above 2.0 mA. The cattle were expressing the learned escape response to avoid shocks above 2.0 mA. The response rate was 96.7% at 5.0 mA. An escape function was calculated by logit regression analysis for the 2.0 to 5.0 mA shock range. The escape function and its associated 95% confidence interval are shown in Fig. 3. Experiment 3B—Learned Escape Response, Mouth-All Hooves Shock Equipment and Procedure Using the same facility as Experiment 2B, seven cows were subjected to mouth-all hooves shocks. A characteristic response of opening the mouth was observed for electrical shock via this path. For this experiment, the cattle were trained by ten "warm-up" trials of 5 mA. The current was terminated when the cow displayed the mouth opening response. This response occurred on 90% of the warm-up trials in less than 10 seconds. The cattle were then exposed to the same series of sixty shocks as in the previous experiment. -V 2.0 Current, m A 0.0 1.0 2.0 3.0 4.0 5.0 ** p < 0 . 0 1 1510 Response, 0.0 13.8 30.0 69.2 92.3 98.4 Difference, 13.8** 16.2** 39.2** 23.1** 6.1 SE, < 4.3 5.7 6.5 6.2 4.5 4.0 5.0 Fig. 3—Response rate vs. current for front-rear hooves shock—Experiment 2B. The statistical comparison procedures were identical with Experiment 2B. Only the first five replicates of each shock intensity were used for one cow. She altered her response from a mouth opening response in the first five replicates to a hoof movement response in the second set of five replicates. The reason for the change in response is not known. Results The observed response frequencies to mouth-all hooves shocks are presented in Table 7. Significant increases in response rates occurred between each 1.0 mA increment comparison up to the 4.0 mA. Cow response averaged less than 15% at 1.0 mA and exceeded 90% at 4.0 and 5.0 mA. No responses were observed during the control no-shock trials. This result indicates the mouth opening was a specific shockavoidance response. A response function to mouth-all hooves shocks was calculated by logit regression. The function and its associated 95% confidence interval are displayed in Fig. 4. The function shows the variation in response rate by current level. For example, a 2.5 mA current level would yield a 50% response rate. — - :^ _ - / / ^ # - /// /// T A B L E 7. O B S E R V E D P E R C E N T R E S P O N S E BY C U R R E N T L E V E L F O R M O U T H - A L L H O O V E S SHOCKS (n = 6 5 ) . 3.0 CURRENT! MILLIAMPERES) irK / p- / S L / / / ., 95 % CONFIDENCE INTERVAL /// *- V/ - ^ .y # •— i — 1 1 1 2-0 1 1 3.0 1 1 4.0 1 1 CURRENT ( MILLIAMPERES) Fig. 4—Response rate vs. current for mouth-all hooves shock—Experiment 3B. T R A N S A C T I O N S of the ASAE—1983 6.0|— FRONT-REAR HOOVES SHOCK POPULATION RESISTANCE PERCENTILES MOUTH-ALL HOOVES SHOCK POPULATION RESISTANCE PERCENTILES 4.0 \- o 9 2.0 ^°'» 1.0 20 40 60 80 100 RESPONSE RATE (%) Fig. 5—Voltage vs. response rate for mouth-all hooves shock. Fig. 6—Voltage vs. response rate for front-rear hooves shock. SUMMARY AND INTERPRETATION Significant variation in resistance was found between pathways through individual cows and between cows. The lowest resistance appeared to be the mouth-all hooves pathway with a mean of 359 ohms. The distribution for this pathway showed 25% of the population below 302 ohms and 75% below 441 ohms. The hoof resistance was found to be a large component of path resistance. However, correlation of resistances with body parameters was inconclusive. Both of these areas need further investigation. In the behavioral experiment phase, no suppression of a learned response to obtain feed was found for up to a 6.0 mA front-rear hooves shock. However, muzzle-all hooves shocks as low as 1.0 mA suppressed plate pressing behavior. A specific avoidance response to a mouth-all hooves shock was exhibited 13.8% of the time at 1.0 mA and 92.3% at 4.0 mA, while a learned escape response to a front-rear hooves shock above a normal activity level occurred between 2.0 and 3.0 mA. At a 5.0 mA level, a 96.7% escape response was exhibited. An indication of the required voltage drop across the animal pathway for a given response rate can be obtained by combining the current response and pathway resistance data. This transformation assumes that current sensitivity is not a function of pathway resistance. A plot of voltage versus response rate for mouth-all hooves shocks is shown in Fig. 5. The family of voltage response curves was drawn based on the pathway resistance percentile distribution. As an example, this plot indicates that at 1.0 V across the mouth-all hooves pathway, 90% of the population would respond 28% of the time, 50% would respond 50% of the time, 10% would respond 92% of the time. Fig. 6 gives a similar plot for front-rear hooves shocks. In this case, there is a base response rate of approximately 20%. Above the base rate, the effects of the current can be seen. For example, at 2.0 V, 50% of the population can be expected to respond 37% of the time. This represents a 17% response rate above the base level. 1983—TRANSACTIONS of the ASAE View publication stats Reference 1. Azrin, N. H. and Holz. 1959. Punishment and recovery during fixed-ratio performance. J. Exp. Anal. Behav. 2:301. 2. Cloud, H. A., R. D. Appleman and R. J. Gustafson. 1981. Stray voltage problems with dairy cows. North Central Regional Extension Publication No. 125. Agric. Ext. Service, University of Minnesota. 3. Craine, L. B., M. H. Ehlers and D. K. Nelson. 1970. Electric potentials and domestic water supplies. AGRICULTURAL ENGINEERING 51(4):415. 4. Fairbank, W. and L. B. Craine. 1978. Milking parlor metal structure-to-earth voltages. Western Regional Agricultural Engineering Service. H-2. 5. Henke, D. V., R. C. Gorewit, N. R. Scott and D. M. Skyer. 1982. Sensitivity of cows to transient electrical current. ASAE Paper No. 83-3029, ASAE, St. Joseph, MI 49085. 6. Lefcourt, A. 1982. Behavioral responses of dairy cows subjected to controlled voltages. J. Dairy Sci. 65:672. 7. Masterton, F. A. and B. A. Campbell. 1969. Techniques of electric shock motivation. In: Methods of psychobiology. Volume 2. (R. D. Myers, ed). Academic Press, New York. 8. Phillips, D. S. M. and R. D. J. Parkinson. 1963. The effects of small voltages on milking plants: their direction and elimination. Dairy Farming Annual, p. 79. 9. Surbrook, T. C. and N. D. Reese. 1981. Stray voltage on farms. ASAE Paper NO. 81-3512, ASAE, St. Joseph, MI 49085. 10. Whittlestone, W. G., M. M. Mullord, R. Kilgour, and L. R. Cate. 1975. Electric shocks during machine milking. New Zealand Vet. J. 23:105. 11. Williams, G. F. 1981. Stray electric current: economic losses, symptoms, and how it affects the cows. Proc. 20th Ann. NMC Mtg., Louisville, KY. p. 13. 12. Woolford, M. W. 1972. Small voltages on milking plants, proc. 2nd Sem. Farm Machinery and Eng. 41-7. 13. Woolford, M. W. 1973-1974. The effects of intermittent electric shocks on milk production and animal behavior. Ann. Rep. Agr. Res. Dir. New Zeal. Dept. Ag. p. 79 (abst.). 14. Woolford, M. W. and P. J. A. Copeland. 1969-70. Effect of transient voltage pulses on milking performance. Ann. Rep. Agr. Res. Div. New Zeal. Dept. Ag. p. 13 (abst.). 1511
