Chilled drinking water effects on lactating Holstein cows in summer

Area of Science:

• Animal Science
• Dairy Science
• Animal Physiology

Background:

• Water temperature is a critical environmental factor influencing dairy cow health and productivity.
• Lactating cows have high water requirements, and thermal stress can negatively impact their well-being.
• Understanding the effects of water temperature on physiological responses is crucial for optimizing dairy farm management.

Purpose of the Study:

• To investigate the impact of different drinking water temperatures on the physiological responses, water intake, and feed consumption of multiparous lactating cows.
• To evaluate the effects of cold (10°C) versus thermoneutral (30°C) water on respiratory rate, rectal temperature, and rumen motility.
• To determine the influence of water temperature on feed dry matter intake and milk yield.

Main Methods:

• Experiment 1: A switchback design with 12 lactating cows offered water at 10°C or 30°C for specific periods, with physiological parameters and intake measured.
• Experiment 2: A 48-hour comparison of ad libitum water intake at 9.5°C versus 27.5°C in the same cows.
• Measurements included respiratory rate, rectal temperature, rumen motility, water consumption, feed dry matter intake, and milk yield.

Main Results:

• In Experiment 1, cows offered 10°C water consumed less water during the hot period (1235-2000 h) but the cold water absorbed more heat. No significant differences were observed in respiratory rates, rectal temperatures, rumen motilities, or milk yield.
• Cows drinking 10°C water consumed more feed dry matter (3.67 kg/100 kg body weight) compared to controls (3.36 kg/100 kg body weight).
• Experiment 2 showed a tendency for cows to consume more water and exhibit lower respiratory rates and body temperatures when offered colder water (9.5°C).

Conclusions:

• Providing 10°C drinking water to lactating cows did not negatively impact their physiological status or milk production.
• Cold water consumption (10°C) was associated with increased feed dry matter intake in lactating cows.
• Further research is warranted to explore the potential benefits of cooler drinking water on dairy cow performance and thermoregulation, especially under heat stress conditions.