Water temperature impacts water consumption by range cattle in winter

Area of Science:

• Animal Science
• Ruminant Nutrition
• Environmental Physiology

Background:

• Water consumption and dry matter intake (DMI) are positively correlated in cattle.
• Ingesting cold water or frozen forage can temporarily reduce rumen temperature, potentially impacting digestion.
• The energetic cost of maintaining rumen temperature when consuming cold water is a concern for livestock, especially during winter.

Purpose of the Study:

• To investigate the effects of providing warm drinking water on in situ nutrient disappearance and rumen temperature stability in cows during winter.
• To determine if warm water consumption influences water intake, body weight (BW) loss, and other performance indicators in grazing cows.
• To quantify the energetic costs associated with drinking water at temperatures below body temperature for range cows.

Main Methods:

• Experiment 1: In vitro incubation of ruminal extrusa at various temperatures (31-39°C) to assess gas and nutrient disappearance.
• Experiment 2: In vivo monitoring of rumen temperature in cannulated cows receiving either cold (8.2°C) or warm (31.1°C) water, with in situ NDF disappearance measurements.
• Experiment 3: Field study measuring daily water intake and cow behavior in paddocks with different water temperature treatments over three winters.

Main Results:

• In vitro NDF disappearance and gas production were reduced at incubation temperatures below 39°C.
• Cows provided warm water maintained a more stable rumen temperature, with less time below 38°C compared to cows drinking cold water.
• Warm water consumption increased overall water intake by 30%, but did not significantly alter in situ nutrient disappearance, BW gain, or calf birth weight.

Conclusions:

• Consuming water below body temperature incurs energetic costs for range cows, primarily related to maintaining rumen temperature.
• While warm water increases intake and improves rumen temperature stability, these benefits did not translate to improved growth or reproductive performance metrics in this study.
• The energetic savings from warm water were less than the heat increment, suggesting other factors may limit performance gains in winter grazing systems.