title: Chilled drinking water effects on lactating Holstein cows in summer.
abstract: In Experiment 1, 12 multiparous lactating cows (six per group) were offered drinking water ad libitum at temperatures of 10 or 30 degrees C in a switchback design. The treatment group received 10 degrees C water from 1235 to 2000 h and was then changed to 30 degrees C water for the remaining 16.5 h/d. The control group received 30 degrees C water 24 h/d. Respiratory rates, rectal temperatures, and rumen motilities were measured at 1100, 1440, and 1810 h, 3 d/wk. Water consumed was recorded for 1235 to 2000 h and 2001 to 1234 h of the next day. Water consumption for the treatment group was 3.90 L/h per cow compared to 5.40 L/h per cow for the control group from 1235 to 2000 h. However, the 10 degrees C water absorbed 65.6 kcal/h more heat than the 30 degrees C water. No differences were found in respiratory rates, rectal temperatures, rumen motilities, or milk yield. Cows that drank 10 degrees C water consumed 3.67 kg of feed DM/100 kg of body weight compared with 3.36 kg of feed for the controls. In Experiment 2, the same two groups of cows were offered 9.5 degrees C water ad libitum for 24 h/d or 27.5 degrees C water for a 48 h comparison. The treatment group tended to consume more water than the control group and to have lower respiratory rates and body temperatures.
authors.affiliation: Department of Animal Science, Texas A&M University, College Station 77843.
authors.forename: C C
authors.initials: CC
authors.lastname: Baker
authors.forename: C E
authors.initials: CE
authors.lastname: Coppock
authors.forename: J K
authors.initials: JK
authors.lastname: Lanham
authors.forename: D H
authors.initials: DH
authors.lastname: Nave
authors.forename: J M
authors.initials: JM
authors.lastname: Labore
authors.forename: C F
authors.initials: CF
authors.lastname: Brasington
authors.forename: R A
authors.initials: RA
authors.lastname: Stermer
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D007774:Lactation / Q000502:physiology*; D011247:Pregnancy; D012621:Seasons; D013696:Temperature; D014881:Water Supply