Severe to extreme to exceptional drought is making an unwanted appearance across 20 states, scorching pastures and affecting hay yields as well as causing heat stress and cattle deaths (see U.S. Drought Monitor).

The highly publicized deaths of 15 Texas cattle, after eating Tifton 85 bermudagrass – erroneously reported in the popular press as a genetically modified crop – were followed by reports of two more deaths in Arkansas.

The Texas animals died with clinical signs and preliminary diagnostic results consistent with prussic-acid poisoning (see “Prussic-Acid Cattle Deaths Isolated, Experts Say”)The Arkansas cattle were positively identified with prussic-acid poisoning as well, although likely from johnsongrass (see "Death By Prussic Acid In Drought-Stressed Forage").

Extension specialists and climatologists across the country are issuing warnings and urging precautions. Here are a few of those warnings:

Kentucky: It’s hot and dry and forages “continue to suffer,” according to University of Kentucky Extension forage specialists Garry Lacefield and Ray Smith in their Forage News newsletter. They urge producers not to waste forage. “There are no silver-bullet management strategies. Use wise grazing management, and for those who are feeding hay, certainly we want to minimize waste during feeding.”

Only warm-season annuals (including sorghum, sudangrass, pearl millet, soybeans and teff) have the potential to produce forage now, the experts say, but all need water to germinate and grow. They remind producers that some of the forages have potential to produce prussic-acid and nitrate poisoning.

Colorado: Devastating wildfires have taken the front row on drought affects in Colorado. But growers there – and in other areas of the country – should be concerned about harvested forage accumulating excessive levels of nitrates after being grown in droughty conditions.

Pigweeds, lambsquarters, oats, millets, sorghums, sudangrasses and corn are often high in nitrates. Under extreme conditions, other grasses and legumes can accumulate nitrates, according to Colorado State University experts.

They suggest having forages tested for nitrates. Then, if there is suspicion of high nitrates or a history of water problems, have water sources tested.

Blend high-nitrate feeds, if possible, with feeds known to have lower nitrate levels. This is also the year to test cornstalks and late cuttings of sorghum or sudangrass, the researchers add.

Kansas: Last week’s heat wave and high humidity across Kansas caused stress to livestock and producers, indicates Kansas state climatologist Mary Knapp in an audio report with K-State Research and Extension News.

Relief isn’t immediately in sight. This week of July 1-7, expect a marginal cool-down, with temperatures in the upper 90s to around 100°F rather than the 114° highs of last week, Knapp adds.

As the mid-week July 4 holiday approaches, “be very cautious about anything that will generate a spark. We’re talking cinder-box conditions,” Knapp says.

For the full audio report, visit here and play the 6/29/2012 audio headed “State climatologist Mary Knapp.”

Wisconsin: Although not cited on the U.S. Drought Monitor, southern Wisconsin is creeping toward drought conditions while northern parts of the state are receiving plentiful rain, says Bill Bland, University of Wisconsin-Extension ag climatologist.

“We started the growing season with drought sneaking into the northwestern half of the state, and now it is the southeastern half that is dry,” says Bland. “The southern tier of counties is presently short of rainfall by at least 2”, a serious deficit coming on the heels of the exceptionally early start to the growing season.” For more information, see "Southern Wisconsin Looks Droughty."

Across The U.S.: Very hot temperatures will affect most of the country from the Intermountain Basins to the East Coast, according to the most-recent U.S. Drought Monitor report. This temperature pattern is expected to continue for July 3-11, with below-normal precipitation stretching from the Intermountain Basins to the Central and Southern Plains, across the Midwest to the interior Northeast.

Above-normal precipitation may occur over New Mexico, from coastal Florida to South Carolina, and (early in the period) over the Upper Mississippi Valley. Northern Alaska is expected to be drier and warmer than normal, and southern coastal Alaska wetter and cooler than normal.