Triple-digit temperatures are the latest weather factor that is making for a tough year for crops and livestock in California.

First, it was the continuous rainfall and cool temperatures in late spring that plagued crops, delayed plantings, halted production and raised disease pressures in many fields.

Now the quick onset of sweltering summer heat-reaching above the century mark in many parts of the state-has brought other concerns and challenges, many of which may have a lingering effect long after summer ends.

Farmers and ranchers are wondering when they are going to get a break, as the long-range forecast calls for continued temperatures near or above 100 degrees particularly in the Central Valley and Southern Desert regions.

Dairy producers are having an especially tough year. The long, wet spring put a damper on quality hay that dairy cows depend on to produce milk. Coupled with the effects of the recent heat wave, milk production could be down by 15 percent to 20 percent, said Juan Guerrero, a University of California farm advisor in ImperialCounty.

"When it gets hot, cows eat less to cool down," said Guerrero, a livestock specialist. "In the feedlots, they don't gain as much weight. The dairies don't produce as much milk. And when it really gets hot, the cows start to ovulate less and the reproduction rates really go down, so they get the double-whammy of less milk and fewer calves."

To relieve some of that heat, dairy producers run cooling systems, he said. Using sprinklers and fans in combination, they are able to bring temperatures down by 15 to 20 degrees, he said.

"This is the time of year when the demand for milk is really high--not because of the school-lunch program, but because it's summertime and its ice cream time," he said. "This is when there's a real peak in the production because of ice cream."

Dave Roberti, who grows hay in Plumas County, said dairy producers typically look to mountain hay during the summer for higher-quality feed because hay produced in the valley during the summer months frequently fails to make the nutritional grade that dairies require. But this year, the heat has degraded much of the mountain hay as well.

"The hot weather stresses the alfalfa, makes it grow a lot faster, which lowers the quality of the hay," said Roberti.

To help milk production, some dairy producers alter the feed to reduce the heat that is produced when the animal consumes a meal, said Carol Collar, a UC farm advisor in KingsCounty who specializes in dairy livestock.

"They might reduce the amount of roughage or the real fibrous part of the ration and increase the grain a little bit," she said. "Other things would be like feeding fat because fat has a real low heat increment and doesn't produce a whole lot of heat. They want to avoid real dry, dusty feed and try to include wet feed into the ration, things like silage and things that have a little more moisture."

In feedlots and irrigated pastures, beef cattle are seeking shade and water, and ranchers are letting their herds lie idle to reduce heat stress.

"You don't work them; you don't move them," said Larry Massa, a GlennCounty cattle producer. "Presently, I wasn't planning on processing or working or vaccinating any cattle. We normally wait for cool days for that."

Denis Lewis, a San JoaquinCounty cattle producer, said he typically irrigates his pasture every 15 days, but with July's scorching temperatures; he is now watering every eight to nine days.

In addition to cattle, the sweltering heat is having negative affects on poultry, grapes, fruit, and nut production. However, some crops, such as melons, cotton and citrus, are doing well with the extended summer heat.

CaliforniaFarm Bureau Federation