Association between neutral-to-earth and cow contact voltage on New York dairy farms.

Cow contact (or "stray") voltage has been associated with various health and management problems in dairy cows. Neutral-to-earth voltage (voltage between the service entrance neutral bus and a reference ground rod) has been equated with cow contact voltage in previous research. To investigate the association between these two voltages, single ("instantaneous") and continuous voltmeter measurements were made at 97 farms in New York. A small positive correlation was found between all single neutral-to-earth and cow contact measurements. Eleven farms with continuous neutral-to-earth readings of .5 V or greater were resurveyed. Eight of the resurveyed farms showed a small or nonexistent correlation between the two voltages. Neutral-to-earth voltage is not recommended as an indicator to predict the presence or magnitude of cow contact voltage.