Effects of drinking water temperature on production responses in lactating Holstein cows in summer

During late summer, 24 lactating Holstein cows were offered 10 or 28 degrees C (control) drinking water ad libitum at 1400 h for 10 min to investigate the effects on respiration rates, body temperatures, dry matter intake, and milk production. Experimental design was a 2 X 3 factorial arrangement of the two drinking water temperatures with .8, 1.1, and 1.4% dietary potassium associated with another experiment. Following 1 wk adjustment and 1 wk standardization, cows were blocked by dry matter intake as a percentage of body weight within parity and randomly assigned to treatments within blocks. Cows were denied access to water from 0900 until 1400 h. Respiration rates and rectal temperatures were recorded before and after watering. Tympanic membrane temperatures (8/h) were recorded during the comparison period using 4 cows per water treatment. No interaction occurred between water and potassium. Water at 10 degrees C had a greater cooling effect than 28 degrees C water. No differences were found between treatments in respiration rates and rectal temperatures after drinking water was temperatures after drinking water was offered. Chilled drinking water decreased tympanic membrane temperatures, which remained lower longer. Cows that drank 10 degrees C drinking water increased dry matter intake and milk yield.