title: Responses of lactating Holstein cows to chilled drinking water in high ambient temperatures.
abstract: In Experiment 1, 12 lactating Holstein cows were provided drinking water of either 10.6 or 27.0 degrees C for 24 h/d in a changeover design to examine the effects of water temperature on feed intake, water intake, respiration rate, rectal temperature, plasma thyroid hormone concentration, and milk yield. The 1st wk of each 3-wk treatment period was for adjustment and the next 2 wk were comparison periods. Least squares means for DM intake as a percentage of body weight were 3.68 and 3.57 for 10.6 and 27.0 degrees C treatment groups. Water intakes in liters per kilogram of dry feed consumed as a percentage of body weight were 21.3 and 20.3. Respiration rates were 70.5 and 81.0 breaths per minute; rectal temperatures were 39.7 and 39.9 degrees C, Triiodothyronine averaged .88 and .75 ng/ml; thyroxine, 42.4 and 39.2 ng/ml; cortisol, 3.03 and 2.06 ng/ml; and progesterone in milk, 4.58 and 3.15 ng/ml for the 10.6 and 27.0 degrees C treatment groups. Milk yield averaged 25.9 and 24.7 kg/d and FCM averaged 25.6 and 23.6 kg/d, respectively. In Experiment 2, 24 cows given a choice of chilled or warm water showed a clear preference (about 98%) for the warm water. If cows are given chilled water of 10 degrees C continuously, no warm drinking water should be available. Chilled drinking water lowered respiration rates and body temperatures and increased feed intake and milk yield.
authors.affiliation: Department of Animal Science, Texas A&M University, College Station 77843.
authors.forename: D L
authors.initials: DL
authors.lastname: Wilks
authors.forename: C E
authors.initials: CE
authors.lastname: Coppock
authors.forename: J K
authors.initials: JK
authors.lastname: Lanham
authors.forename: K N
authors.initials: KN
authors.lastname: Brooks
authors.forename: C C
authors.initials: CC
authors.lastname: Baker
authors.forename: W L
authors.initials: WL
authors.lastname: Bryson
authors.forename: R G
authors.initials: RG
authors.lastname: Elmore
authors.forename: R A
authors.initials: RA
authors.lastname: Stermer
mesh_terms: D000818:Animals; D001831:Body Temperature; D001835:Body Weight; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D004326:Drinking; D004435:Eating; D005260:Female; D006813:Humidity; D006854:Hydrocortisone / Q000097:blood; D007774:Lactation; D016018:Least-Squares Analysis; D008892:Milk / Q000032:analysis / Q000378:metabolism; D011374:Progesterone / Q000032:analysis; D011897:Random Allocation; D012119:Respiration; D013696:Temperature; D013963:Thyroid Hormones / Q000097:blood; D014867:Water
chemical_list: D013963:Thyroid Hormones; D014867:Water; D011374:Progesterone; D006854:Hydrocortisone