Dairy, Pig Farmers Roll With the Heat

8/3/2013 7:00 AM
By Philip Gruber Staff Writer

The first major heat wave of the summer hit Pennsylvania last month, but Zach Meck’s 230 cows did not seem to mind the mercury spike.

This year, Meck installed the CowKühlerZ system at Meck Brothers Dairy in Womelsdorf, which he owns with his brother Jeremy.

Even with temperatures approaching 100 degrees outside, the cows were “acting like it was a normal day,” he said. The cows were not hot and were chewing their cud in their stalls.

Suzanne Meck, Zach’s wife and the East Coast marketing director for the cooling system, said that laying down is a good sign.

In many systems, cows can only stay cool by standing under the sprinkler located at the feed bunk, whereas CowKühlerZ can be installed over stalls, bed pack or the feeding area. It also uses larger water droplets than other sprinklers.

Larger droplets are better, writes Mark Whitney, a University of Minnesota Extension educator, because they allow more of the water to reach the animal rather than turning into unhelpful mist.

Smaller droplets can merely humidify the air, which decreases the difference between an animal’s humidity and the air’s and thus slows evaporation.

Suzanne Meck said the company saw a big jump in phone calls the week before the heat wave, as farmers looked for ways to prepare for the forecasted temperatures.

Zach Meck said other factors at his dairy made it difficult to tell whether he had lost yield during the hot spell, but he did not expect the heat had hurt the number much. He did not change the cows’ dry feed during the heat wave.

Andy Bollinger of Meadow Spring Farm in Lititz is also working on upgrades that will increase cow comfort for his 360 animals.

“We have fans everywhere, and we need to put more in,” he said.

Extension agricultural engineer Dan McFarland did wind tests in the barn recently, and some areas were “a little dead as far as air movement,” he said.

Bollinger has not decided where to put the fans yet. He would consider doing the project this year or during the cooler months, but he wants to make sure he does not put it off until the first heat wave of next year.

He also has sprinklers over the feeding area that run for about one minute every 10 minutes. He plans to add other sprinklers to the pre-milking holding area soon.

“Most people will tell you it’s the most important place” for sprinklers, he said.

He lost five to six pounds of production the week of July 7. Production stayed low but did not decrease any further during the heat wave the following week, he said.

No matter how the cooling is achieved, keeping cows from feeling the heat is essential to maintaining profitability during the summer, said Emily Yeiser, dairy initiative manager at the Center for Dairy Excellence.

Cows are more heat-sensitive than humans and start to be affected when the temperature passes 65 degrees, she said.

“It’s kind of like humans; when it gets really hot out, you don’t want to eat a whole lot,” she said.

And when cows eat less, they also make less milk. Fans, sprinklers and misting systems are the main cooling technologies dairy farms use to beat the heat. Air conditioning is essentially unheard of in the dairy industry, she said.

Automated fan systems can now be set to turn on when the temperature rises by as little as 1 degree. The fans run even in the winter. The air is cold, but cows prefer a breeze over stagnant air, she said.

Tunnel ventilation can provide more air flow as well, she said.

Cows are no longer allowed to cool off in creeks or streams because of water-quality initiatives to protect the Chesapeake Bay watershed, she said.

From what Yeiser noticed last week, the effects of the heat wave were “nothing outside what you would expect.”

Milk yields were dropping slightly, fans were running longer and sprinklers were running more often, but she had not heard of any farmers having major issues.

Pennsylvania dairy farmers are fortunate to have “a lot of infrastructure” in the state, Yeiser said, so that if they do have a problem with their cooling systems, a service technician is usually available to fix the problem in a reasonable time.

Dan McFarland, the Extension agricultural engineer, offered the SAAWW acronym for minimizing the effects of summer heat on dairy yields.

S stands for shade. Just like humans, cows can bear the heat better when out of direct sunlight. Shade can easily be found in the barn or under tree cover.

The first A is for air exchange. Replacing the air around the cows is important for removing moisture, heat and pollutants, he said. Hot cows breathe faster to remove heat from their bodies, but that breathing puts a lot of water into the air. Fans replace the stuffy, humid air with dry air.

The second A is for air movement. The idea is to disturb the layer of air around the cow. As cows release heat into the air, fans can take the heated air away and replace it with new air.

The two A’s need to be used together, McFarland said, because air movement without air exchange will just push uncomfortable air around.

The first W is for water drinking. Cows can easily require 20 percent more water during hot spells. Dry cows and young cows might even double their consumption, he said.

It’s no wonder. A mature Holstein can expel seven gallons of water a day simply through respiration, and that water needs to be replaced, McFarland said.

The second W stands for water for evaporative cooling.

Direct evaporative cooling uses a sprinkler system to intermittently soak the cow to the skin and then allows the water to evaporate. Fans help speed the process.

Indirect evaporative cooling takes moisture from the air, increasing the temperature difference between the cow and the air. As the difference increases, heat transfer from the cow to the air accelerates.

A cow’s internal body temperature is 101.5 degrees, and cows start being bothered by the heat when their core rises to 102 degrees or more. Simply getting the cow back to its normal internal temperature can make a big difference in the animal’s comfort, he said.

Night cooling is also an important heat-abatement technique that requires no mechanization. If the temperature falls below 70 degrees when the sun goes down, the cow can get back to a comfortable temperature by early morning.

Recent nights with high dew points and temperatures that have not fallen much below 75, however, have blunted the effectiveness of night cooling, McFarland said.

Managing cow comfort is important because the heat can cause cows to drop milk productivity by 10 to 25 percent. Higher-producing cows tend to see a sharper drop in milk than less productive animals, he said.

Hot cows are also less inclined to express estrus, which can hinder conception by a month or two and therefore delay the cow’s next lactations, McFarland said.

While many of the same principles for beating the heat apply to swine production, pig farmers have special considerations, too, according to a report by Mark Whitney, the Minnesota Extension educator.

Like other animals, heat-beat pigs will suffer reduced growth and reproduction. Heavier pigs are affected more by the heat because they have a lower optimum temperature, he writes.

Pigs can be helped both by “increased heat dissipation and reduced production of body heat,” Whitney writes.

Pigs remove heat by sprawling on the barn floor to increase contact with the cool surface. They also pant because they do not sweat.

Like cows, pigs must increase their water intake in the summer. A gestation sow can use six gallons of water a day during hot weather.

Unlike cows, wild pigs or farm pigs from earlier times wallowed in mud to keep cool.

“The mud itself does not provide significant cooling directly, but instead evaporative cooling occurs as the mud dries, while it also provides a protective barrier against the sun,” Whitney writes.

In the absence of unsanitary muddy sties, modern farmers can use sprinklers to cool their hogs. Whitney suggests a setting of one to two minutes of spraying every 30 minutes.

Sows alone in farrowing or gestation stalls can also receive a water drip paired with air movement. Just make sure the water is more or less evaporated before it hits the stall floor, Whitney advises.

Pigs will also avoid producing body heat by eating less. Summer feed therefore needs to be packed with more nutrition so that the pig keeps gaining weight despite cutting back on their intake, he writes.

Farmers should add to the feed more fats like beef tallow, choice white grease and vegetable oil. These hold more calories and release less heat during digestion.

Swine owners should avoid fiber-heavy offerings like soybean hulls and alfalfa, which do not give a lot of nutrition and make a lot of heat when digested, Whitney writes.

Increasing the floor space per pig — to three or four square feet for nursery pigs and about eight for finishers — can keep the animals from transferring heat to each other.

If pigs or other livestock are pastured, outdoor shelters with reflective metal roofs are best because they bounce the sun’s rays off, Whitney writes.

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