Released August 8, 2008
The Davis Enterprise Reprinted with permission
Heifer No. 2165 hogged the shower.
Standing in the sun, the temperature around her in the low 90s, she chewed cud, now and then giving a slow head shake or swishing her tail. Water from two shower heads sprayed down on her shoulders and hindquarters.
All in all, life looked pretty good.
It may appear that Cassandra Tucker, an assistant professor of animal science, is running a spa for dairy cattle in a UC Davis barn, but her research is serious business.
Heat stress reduces a cow’s milk output by 3 to 10 percent because the animal is using more of its energy to keep cool. That costs dairy producers $900 million annually. To combat it, farmers turn to misters attached to feeding troughs.
Tucker is working to better understand how and when cows prefer to make use of cooling water.
Two months into her project, she's found that "cows have very different personalities" when it comes to cooling off.
"Some really love it," she said. "They'll spend seven hours a day in the shower. Others use it less, maybe an hour a day."
Her research, funded by a $20,000 grant from the Whole Foods Market Animal Compassion Foundation, is also timely: The public has taken a growing interest in farm animal comfort.
Cartons of Clover Stornetta brand milk, for example, note that their cows are "free farmed" under standards set up by the American Humane Association.
And this fall, Californians will vote on Prop. 2, which if passed would mandate that certain animals be able to turn around freely, stand up, lie down and extend their limbs.
Needless to say, high-end, made-for-human-style shower heads wouldn't be included.
Tucker's experiment makes use of four Holsteins at a time, two cows and two heifers. Each is assigned a stall measuring maybe 30 feet by 15 feet, about a third of it shaded, with bedding, food and water.
Nice enough, but one cow and one heifer get a bonus: a cube-shaped wooden structure, measuring about 8 feet by 8 feet rigged with two shower heads. They hover above a platform which, when 20 pounds or more of pressure per square inch is applied to it, turns the shower on.
It can take anywhere from a couple of hours to a full day to teach the cows to trigger the showers. Once the bovines learn, they're monitored closely for five days.
Thirteen security cameras keep an eye on those with showers and the control cows without, tracking when showers are used and on what part of their bodies, when they eat or drink and how much, when they lie down, when they stand in the shade.
Devices placed in their reproductive tract collect their core temperatures every five minutes. Their skin temperature is checked regularly, as is their breathing rate.
So far, the showers have made a dramatic difference. On a day when the temperature broke 110 degrees, control cows were taking 100 breaths a minute; those in the showers, which are kept at a steady 79 degrees, took just 60 breaths per minute.
Skin temperature has measured 95 degrees across the study. Control cows' skin has reached 100 degrees, while those with access to showers have lowered theirs to 90 degrees. The cows definitely seem to enjoy the showers.
So much so, in fact, that when the experiment began, Tucker had to change her plan to place two cows in each pen. That's because one cow would begin guarding the shower from the other, like teenagers squabbling over the family bathroom.
Tucker is not tracking the amount of milk from her subjects, who are not lactating.
As Tucker talked, No. 1991 stepped onto her platform. The spray began. The cow put out her long tongue. Drinking that way hasn't been common, so far, Tucker said.
Of the six animals who've had access to showers for which the videotapes have been analyzed, three stood under the showers for more than two hours a day.
Tucker, brushing away flies in the barn, looked toward heifer No. 2165.
The black spot on her back glistened. Her ear tags dripped. She showed no sign of budging. Said Tucker, "She is clearly going into the high shower user category."
Because the cows have varied so much in their shower use, Tucker speculates that some may prefer to cool down using misters at different times, for different lengths of time.
Giving cows that choice is a logical next step in Tucker's research, which she's performing with research technicians David Ledgerwood and Amanda Grout and student assistant Geoff DeJanes.
They've already discovered that the showers draw other animals.
"We're getting a lot of ducks coming to visit," Tucker said. "Luckily, they're not heavy enough to turn on the water themselves."
— Cory Golden, The Davis Enterprise, (530) 747-8046, cgolden@davisenterprise.net
Copyright, 2008, The Davis Enterprise. All Rights Reserved.
--30--
Contacts: Cassandra Tucker, cbtucker@ucdavis.edu
Pat Bailey, (530) 752-9843, pjbailey@ucdavis.edu
