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Little improvements offer big relief for cow heat stress

Adjusting fans to a 90-degree angle made a huge difference on Hidden View farm in Champlain, N.Y.

Chris Torres, Editor, American Agriculturist

July 6, 2020

6 Min Read
Cows stay cool under fans at Hidden View Farm in Champlain, N.Y.
IMPROVING COW COMFORT: At Hidden View Farm in Champlain, N.Y., Dale Tetreault says that changing the angle of the fans and closing a barn helped increase butterfat and protein, leading to a better milk check. Photos courtesy of Dale Tetreault

Cow comfort is always important if you want cows to produce the most milk. It’s even more important during summer as production usually decreases when the heat is on.

At Hidden View Farm in Champlain, N.Y., just south of the Canadian border, cow comfort can be a challenge in the summer heat, even with how far north the farm is. But it doesn’t take the installation of expensive sprinkler systems or reconstructing the barn to make a difference.

Dale Tetreault, owner of Hidden View, says his nutritionist went to two different farms and noticed the fans were turned to a 90-degree angle toward the cows. They also closed the back doors to recirculate the air. Tetreault thought it was something he could do, too.

“We said, ‘What the heck, we have nothing to lose,’” he says. It turned out to make a big difference. “Cows ate twice as much; they were more relaxed and they weren’t bunching anymore.”

Tetreault’s operation was one of four farms to participate in a multiyear study on the effects of summer heat on cow production. The study, supported by the Northern New York Agricultural Development Program, found that giving cows access to more water and better airflow was key to keeping cows comfortable during the hottest days of the year. For many farmers, it’s just a matter of adjusting the fans, closing the barn doors or building another well that can make a big difference.

Hot days have big impact

Researchers looked at heat abatement systems on the farms and measured the Temperature Humidity Index, a combination of the ambient temperature and relative humidity.  

In 2017, the first year of the study, the researchers found that standing time increased the most — by 2.5 hours a day — on a farm with no heat abatement system on days when THI was greater than 68. For farms using box fans in the housing area, standing time increased by 1.2 to 1.7 hours per day.

Lameness increased on all farms, but most significantly on the farm with no heat abatement system. Interestingly, bulk milk protein dropped significantly during the hottest days, and on the farm with no heat abatement it accounted for 32% of the overall bulk tank milk protein variability.

In 2018, a warmer year, the researchers focused on the effects of heat stress on lying behavior, lameness and production. According to the report, all cows were scored at the beginning and end of the study for motion on a flat and level surface. Cows housed in a free-stall pen were scored using a 5-point scoring system: 1 equals normal, 2 equals mildly lame, 3 equals moderately lame, 4 equals lame and 5 equals severely lame.

All farms saw a significant increase in lameness from July to early October. When cows exceeded a lameness score of 2, both dry matter intake and milk yield decreased.  

Just like in 2017, milk protein dropped more on farms with little to no heat abatement systems, accounting for more than 40% of the drop, according to the report.

Katie Ballard, director of research at Miner Institute, which led the project, says that the fact that protein levels decreased with no change in milk fat is likely a reflection of lower dry matter intake and, therefore, reduced microbial protein production and less metabolizable protein supply for protein synthesis.

Water matters

Last year, temperature boluses were added to 30 cows on each farm. The boluses, which sit inside the rectum, measured the temperature of each cow, sending data to a bay station and stored in the cloud.

Cow body temperature increased when it got hot regardless of heat abatement. On the farm with no heat abatement, body temperature was highest during the early morning and late night, especially during heat events.

The process of milking or movement to the holding area with fans and sprinklers helped reduce body temperatures, Ballard says.  

What excited her, though, was seeing that body temperature decreased the more the cows were able to drink water.

“We are pretty excited about this research since it is the only data we are aware of in the U.S. that has observed drinking behavior and body temp using these temperature boluses,” she says. “Water to drink is a big one. There have been folks that have published research that [cows] drink 20 to 30 gallons more during heat events.”

Although windspeed wasn’t measured daily, the greatest amount of air movement was found on Tetreault’s farm stalls. Air movement over the cows, she says, helps to remove heat produced by the cow.

Ballard says that unlike farms in places such as Georgia and Florida, where there are more hot days in summer for cows to get acclimated quicker, there aren’t enough days in summer, especially in the North Country, for cows to get acclimated to the heat. She says it takes around two weeks of heat acclimation to occur in cows.

“You don’t have those two weeks of heat stress here,” she says.

Regardless, the effects of hot weather were much greater than she thought on lying, lameness and overall production.

“Now, what do we do about it is the question, and how much producers need to invest,” she says.

But with the data available, Ballard hopes that just improving airflow by adjusting fans and providing more water will be enough.

Good results

Adjusting the fans and closing the barn door worked out well for Tetreault. He thought overall production would go up because of the improvements he’s made, but he’s seen butterfat and protein go up — average is 4.1% butterfat, 3.2% protein — which is good for the milk check.

He now plans on putting in misters for his closeup group, dry cows and first-cow group. Closing the back doors on the north side of the barn created an air tunnel, and since he uses sand bedding it creates little sandstorms that his employees hate. But it’s more comfortable for the cows and better for production. And it’s also cut down on bunching.

Fans angled so they blow directly on the cows improves their comfort in summer heat
ADJUSTING FANS: Changing the angle of the fans so they blow directly on the cows has made a big difference on Dale Tetreault’s farm, especially during the summer heat. Cows now eat twice as much, are more relaxed and don’t bunch as much as they used to.

“It just worked out really well," he says. “Whatever it is, we got cows using all the stalls now.”

Remember SAAWW

Dan McFarland, a Penn State agricultural engineering Extension educator, says farms should remember the concept of SAAWW — shade, air exchange, air movement, water for drinking and water for evaporative cooling — when thinking of ways to cool down cows.

Little things such as soaking cows in the tie-stall every few hours can make a big difference on a hot day.

“I’ve come across a number of folks with tie-stall barns that will soak cows, in the stalls, with water using a hose or backpack sprayer every three hours or so during a hot day to provide some direct evaporative cooling,” McFarland says. “However, because direct cooling is most effective with air movement, circulation fans are needed over the cows. Also, since additional moisture is added to the environment, a good air exchange is necessary as well.

“I’ve also seen cows ‘cooled’ in a milking center holding area using a hose, and even an oscillating lawn sprinkler mounted upside-down on the bottom chords of the roof trusses. Exposing cows to a clear night sky can also help reduce elevated core temperatures effectively by letting cows out of the barn after the sun goes down.”

About the Author(s)

Chris Torres

Editor, American Agriculturist

Chris Torres, editor of American Agriculturist, previously worked at Lancaster Farming, where he started in 2006 as a staff writer and later became regional editor. Torres is a seven-time winner of the Keystone Press Awards, handed out by the Pennsylvania Press Association, and he is a Pennsylvania State University graduate.

Torres says he wants American Agriculturist to be farmers' "go-to product, continuing the legacy and high standard (former American Agriculturist editor) John Vogel has set." Torres succeeds Vogel, who retired after 47 years with Farm Progress and its related publications.

"The news business is a challenging job," Torres says. "It makes you think outside your small box, and you have to formulate what the reader wants to see from the overall product. It's rewarding to see a nice product in the end."

Torres' family is based in Lebanon County, Pa. His wife grew up on a small farm in Berks County, Pa., where they raised corn, soybeans, feeder cattle and more. Torres and his wife are parents to three young boys.

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