Stray voltage symptoms common in dairy cattle eliminated by on-farm neutral isolation

Abstract

Dairy farmers with stray voltage symptoms in their cattle often spend thousands of dollars to do neutral isolation, which isolates the primary neutral of the electricity provider from the farm neutral to suppress stray voltage from off-farm sources without knowing what results to expect. Dairy cows exposed to stray voltage exhibit behavioral symptoms, milking and production characteristics that are detrimental to their ability to produce milk. This study determined the effects of neutral isolation on these three general classifications of stray voltage symptoms in dairy cattle. A survey of sixty-three dairy farms throughout Wisconsin was done to determine what stray voltage symptoms in dairy cattle were eliminated on these dairy farms that have neutral isolation. This study will serve as a resource for dairymen, agriculture educators, and consultants who deal with the problems and symptoms associated with stray voltage in dairy cattle. To answer the questions of this study, dairy farmers who installed neutral isolation devices to correct the problems associated with stray voltage were sent a mail-back survey. They were asked what common stray voltage symptoms were present on their dairy farms prior to isolation, compared to what symptoms were eliminated by neutral isolation. Questions about type of milking facility, milk production, and cost of isolation were asked. Comments were requested to illicit opinions and comments from participants in the study. The subjects selected for this study were a convenience sample taken from the customer list of Concept Electric Inc., Appleton, Wisconsin. This company specializes in stray voltage testing and neutral isolation. Sixty-three dairy farms throughout Wisconsin that were tested for stray voltage and installed neutral isolation devices to correct stray voltage problems in their dairy cattle were surveyed. Thirty-seven surveys were returned. No follow up survey was sent to the non-respondents because it was an anonymous survey, with no identifiers used. A major finding of this stray voltage study, was that the average increase in milk production was 14.03 pounds of milk per cow per day after neutral isolation on the thirty seven farms that responded to the survey. The mean daily milk production per cow before isolation was 53.97 pounds. The median was 55 pounds of milk with a standard deviation of 11.38 pounds. The mean daily milk production per cow after isolation was 68 pounds. The median after isolation was 70 pounds of milk with a standard deviation of 9.61. Forty-three percent of the respondents spent between $20,000 and $30,000 to install neutral isolation devices to eliminate stray voltage problems on their dairy farms. Another 18.9% spent over $50,000 to correct the problems associated with stray voltage on their farms. To answer the research questions of this study, dairy farmers who installed neutral isolation devices to correct the problems associated with stray voltage were asked what common stray voltage symptoms were present on their dairy farms before isolation, compared to what symptoms were eliminated after neutral isolation. This study found that the percentage of behavioral symptoms reported by the respondents as always present was zero percent after neutral isolation. Both milking parlor and stall barn facilities had the same results. The milking characteristics of milk letdown and milking time were improved by neutral isolation. Two production performance characteristics were surveyed, somatic cell count and incidence of clinical mastitis. Even though increased somatic cell count and clinical mastitis is not caused by stray voltage, the incidence of each was reduced in the findings of this study. Neutral isolation improved the cows’ behavior and milking performance, resulting in a decrease of somatic cell count and incidence of clinical mastitis.