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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Stress on Dairy Cows with Special Reference to Milk Removal and Stray Voltage

Author
item Lefcourt, Alan

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: April 27, 1996
Publication Date: N/A

Interpretive Summary: This report outlines a history of the relationship of stress to efficient milk removal. First, physiological and behavioral effects of stray voltage (exposure to electrical shock) and their relation to efficient milk removal are examined. Specifically, implications of the lack of significant physiological responses to stray voltage, in contrast to the sometimes pronounced behavioral responses, are explored. Next, stress responses to stray voltage and to weaning are contrasted. Finally, change in heart rate, the only physiological measure which showed any consistent relationship to exposure to electrical shock, is be examined as a potential measure of stress in cows. Concluded are that: 1) the relationship of stress to milk removal is probably more confusing for cows than for any other specie, most likely due to the effects of domestication and genetic selection for milk production; a case in point is the lack of significant physiological responses to stray voltage despite sometimes pronounced behavioral responses, and 2) changes in heart rate may be one of the best measures of stress for cows. However, interpretation of changes in heart rate can be difficult, exposure to electrical shock results in only transient increases in heart rate while agonistic encounters can result in dramatic and prolonged increases in heart rate. The final conclusion is that we still have a long way to go in understanding the complexity of responses to stress and how these responses relate to efficient milk removal.

Technical Abstract: This report outlines a history of the relationship of stress to efficient milk removal. First, physiological and behavioral effects of stray voltage (exposure to electrical shock) and their relation to efficient milk removal will be examined. Specifically, implications of the lack of significant physiological responses to stray voltage, in contrast to the sometimes pronounced behavioral responses, will be explored. Next, stress responses to stray voltage and to weaning will be contrasted. Finally, change in heart rate, the only physiological measure which showed any consistent relationship to exposure to electrical shock, we be examined as a potential measure of stress in cows.

Last Modified: 11/24/2014