Cardiovascular responses of cows given electrical current during milking

Area of Science:

• Veterinary Medicine
• Animal Physiology
• Electrophysiology

Background:

• Mammary gland blood flow is crucial for milk production.
• Understanding factors influencing mammary blood flow can optimize dairy practices.
• Previous research has not extensively explored electrical stimulation's effects on bovine cardiovascular responses during milking.

Purpose of the Study:

• To investigate the impact of 4-mA square wave alternating current on mammary blood flow rate, heart rate, and blood pressure in lactating Holstein cows.
• To determine the immediate and sustained cardiovascular effects of electrical stimulation applied prior to and during milking.

Main Methods:

• Six late-lactation Holstein cows were utilized in the study.
• Alternating current (4-mA) was applied to the lumbar-sacral region before and during milking.
• Mammary blood flow, heart rate, and blood pressure were continuously monitored.

Main Results:

• Application of 4-mA alternating current prior to milking caused an immediate 50% increase in mammary blood flow, a 25 beats/min rise in heart rate, and a 33 mm Hg increase in blood pressure.
• Mammary blood flow increased by 30% within 40 seconds of milking without current.
• Milk yield was not significantly affected by the electrical current application.

Conclusions:

• 4-mA alternating current applied before and during milking elicits acute increases in mammary blood flow, heart rate, and blood pressure in dairy cows.
• These cardiovascular responses to electrical stimulation are transient.
• Continuous current application during milking does not alter the physiological increases in mammary blood flow associated with the milking process itself.