Local livestock operators aim to mitigate heat stress

As temperatures rise across the tri-state area, experts say the race is on to keep cows cool.

With summer hitting its stride, local dairy herds are at an increased risk for heat stress — a condition marked by decreased performance, lowered milk production and increased risk of reproductive issues and other health concerns.

Left unchecked, it can even lead to death.

“Think of cows like ice age creatures,” said Larry Tranel, a dairy field specialist at Iowa State University Extension and Outreach’s Dubuque County office. “They do well in the cold, but once it starts to warm up, their performance suffers.”

Some heat stress is unavoidable, Tranel said, but too much can be costly.

Across the national dairy industry, the U.S. Department of Agriculture estimates that more than $1 billion is lost annually as a result of poor performance during periods of heat stress. Those losses come from reduced milk production, as well as negative fertility outcomes and other health concerns.

“It’s not uncommon for cows to drop 5% to 8% of their milk production because of heat stress,” Tranel said. “If you take that and multiply it by every cow in the barn, that can really add up. That’s why farms with better heat stress mitigation plans tend to be more profitable.”

Fortunately, Tranel said, there are avenues available to farmers looking to reduce the risk of severe heat stress and improve animal welfare as temperatures rise. Mitigation plans vary from farm to farm, he said, but usually center on improving ventilation, shade and water access.

Andy and Lyn Buttles have several measures in place to reduce the risk of heat stress at Stone-Front Farm, the 1,400-head dairy operation the couple runs near Lancaster, Wis. Most of those systems are automated and triggered by temperature or cows’ recorded respiratory rates.

Fans keep the barn cool and are automated to kick on according to the temperature, Andy Buttles said. Overhead sprinklers activate once the temperature reaches 72 degrees, misting the cows for one minute every 15 minutes.

Cows can’t sweat like humans do, Buttles said, so the mist allows them to experience the benefits of evaporative cooling, providing cows a kind of relief similar to a breeze brushing the skin of a person who just got out of the swimming pool.

Monitors placed across the operation also measure the average respiratory rate of each pen. If respiratory rates are high, it indicates that the cows in that pen might need additional interventions to cool them down and improve cow comfort.

“We have it all set automatic, so it can happen without someone having to stand right there,” Buttles said. “That way, if we don’t have someone there and it gets hotter than we thought, the system knows to keep up.”

Matt and Natalie Berning have similar methods in place at Berning Acres, the 430-head dairy operation the couple runs at their farm near East Dubuque, Ill., where fans and sprinklers are spread throughout the barn to be activated or accelerated based on the temperature.

The farm’s water troughs also refill automatically to ensure the animals have plenty of access to cool, fresh water. Cows’ water intake increases during hot weather, Matt Berning said, with each cow drinking up to 50 gallons per day.

Those systems run night and day, he added, so cows can recover from the effects of heat stress that can linger even after the sun goes down.

“It can take a cow some time to really come back from a hot day,” he said. “It might cool down at night, but that cow is still dealing with that stress. That’s why when we get these high nighttime lows, it can really be stressful for the cow because it feels like there’s no relief.”

Beef cattle also are susceptible to heat stress, particularly animals that are heavy, dark-hided or have a poor immune system. That stress leads to decreased performance, reduced feed intake and increased health risks.

Interventions for beef cattle carry many similarities to those for dairy herds and revolve around ventilation, water access and shade cover, said Denise Schwab, ISU Extension beef specialist for northeast Iowa.

Beef cattle typically spend more time outside than dairy cattle, so Schwab said ensuring access to shade and room to move around and find a breeze are particularly important. Water troughs also must be large enough to accommodate multiple animals at once to avoid the added heat of cows huddling together.

“Reducing heat stress helps the animals, but it also helps your bottom line,” Schwab said. “That’s why it’s something we think about every year and really try to keep on people’s minds.”