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Heat wave tests California farms, ranches, animals

Issue Date: August 26, 2020
By Kevin Hecteman

A triple-digit heat wave the likes of which had not been seen for nearly 14 years roasted much of California last week, prompting concerns for farm employees, livestock and crops.

Many San Joaquin Valley locales broke records, in some cases with daily highs reaching into the 110s.

Sonoma County wasn't spared, either. Domenic Carinalli Jr., who farms in Sebastopol, had vineyards and a dairy operation to keep cool.

"It's been really hot for the men that are working in the fields," Carinalli said.

He gave his crews extra breaks and, on a couple days, sent them home early when the thermometer approached triple digits.

"We got through the worst of it, and hopefully from now on we're going to be in a little better state," he said.

The heat wave came on top of the COVID-19 pandemic, which already had Carinalli taking precautions.

"In the grapes, everyone basically works individually, so you're not really close to anybody," he said, adding that he had plenty of masks on hand for those who wanted them.

"They wear a mask and stay away from everybody," he said. "It's actually been working pretty good for us."

On his dairy, Carinalli said, he made sure to keep his cows well fed and to provide them plenty of water.

In the southern San Joaquin Valley, memories linger of the 2006 scorcher that took the lives of thousands of animals. That event prompted dairy farmers to become proactive on installing heat-abatement systems, said Daniela Bruno, a University of California Cooperative Extension dairy advisor in Fresno, Madera and Kings counties.

"The best practices I have seen include installation of fans, sprinklers, soakers, shades and water for all animals," Bruno said. "Dairy cattle are most comfortable when the temperature is between 45 to 68 degrees, so feeding animals in the cooler hours of the day also helps in minimizing milk production drop."

Rendering capacity also has been a concern, prompting the California Department of Food and Agriculture to issue a notice spelling out alternatives in case rendering plants reach capacity, said Taylor Roschen, a California Farm Bureau Federation policy advocate.

Through Aug. 31, livestock and dairy producers who need rendering services and cannot find them nearby may use one of four options. The preferred option is to truck the carcass to another plant with rendering capacity. If that's not an option, producers may transport the carcasses to a permitted landfill. The next option is temporary storage on the farm, pending later transfer. The last resort is on-farm composting.

"We understand that these options are not immediately available and will be contingent upon local permitting and rules," Roschen said. "Therefore, we are encouraging the department to coordinate more closely with the Office of Emergency Services and local governments to provide turnkey options and additional funds to manage this issue."

Producers must record the final disposition of carcasses not sent to rendering plants. Questions may be directed to CDFA at 916-900-5004 or

In addition, the California Dairy Quality Assurance Program has released guidance for dairy farmers concerning disposal of carcasses, noting that since mid-August one rendering plant has experienced mechanical issues and a landfill has been closed temporarily by wildfire smoke. The guidance is tailored to each county in the San Joaquin Valley, and generally recommends that carcasses unable to be rendered go to a permitted landfill or be composted on the farm.

The document may be found at

Cattle ranchers with animals on pasture or range tend not to have as many issues, said Rebecca Ozeran, a UCCE livestock advisor in Fresno and Madera counties.

"The forage has been dry for months," Ozeran said. "A lot of it will depend on how much good feed is available, as well as how much water is available."

The heat's effects on animals can linger after the temperature cools, she noted.

"Even if the animals survive the heat of the season, it can still reduce their rates of growth if they're a young, growing animal, and it can reduce the amount of production they have," Ozeran said. "For instance, if you've got a poultry farm that is experiencing the heat, then they may have fewer eggs that are produced for a few weeks to a few months, depending on how long it takes their bodies to bounce back from that heat impact."

Animals might also have reproductive issues, depending on the breeding season, she added.

"Fortunately, out here, most of the cows are going to be having their calves in a couple of months," Ozeran said. "They should be far enough along that they won't have any serious impacts, but there might be increased rates of abortion due to the heat stress right now as well."

In Sonoma County, Carinalli said thunderstorms that started North Bay wildfires gave him trouble in his vineyard.

"With the grapes, it's been completely crazy," he said.

"We got some thundershowers, which is not good when you get a shower on your grapes and it's that hot—it leads to a lot of mold and mildew," Carinalli said. "I've had a really nice, clean crop all year."

So he started treating for mildew the day after the storms passed, as a precautionary measure. As of last week, "I don't see any issues," he said.

The heat also accelerated grape development. Carinalli said he's harvesting grapes for sparkling wine, with other varietals two to three weeks away from being ready.

"We normally have a lot of fog, but of course this year we haven't had hardly anything," he said. "I'd say we're probably two to three weeks ahead of last year on our harvesting."

(Kevin Hecteman is an assistant editor of Ag Alert. He may be contacted at

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.

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