Effect of Stray and High Voltage Exposure on Livestock: An Overview

Abstract

Electricity is essential to dairy farming and  electrically powered machines are used for milking,  automatic feed dispensers and heated water bowls.  Leakage of current from these equipments, high  voltage lines or faulty connections between the  electrical circuit and the earth can lead to an  undesirable electrical phenomenon called stray  voltage. Stray voltage is a small voltage (<10V) that  can be measured between two possible contact  points. Cows can sense voltages at approximately  one-tenth of a human being. Humans have  inherently higher body resistance than cows and  generally have shoes or boots while working in  barns, which further increases resistance.  Consequently, humans do not feel what animals  feel. Stray voltages less than 0.5 volts are  considered normal. Stray voltages vary, depending  on the circuits used and the amount of moisture in  the soil around the grounding rod. Impact of stray  currents on livestock at current 1 - 3 mA: At current  4 - 6 mA: common behavioral response such as  flinching or delaying drinking water. At current > 6  mA (up to 10): Feed intake is reduced, resulting in  lower meat and milk production. Common  symptoms of stray voltage in cows include  hesitation to enter the parlor, they may stampede or  rush out of the parlor when released, cows dance  or step around constantly while in the milking parlor,  Normal milk letdown is interrupted, Increased  milking time, Udder irritation caused by residual  milk and increased somatic cell count which  increases the incidence of mastitis.