An Italian farm became an open-air morgue in early August with about 50 cows poisoned by young sorghum plants, an accident caused by the drought, experts say.
A farm in Sommariva del Bosco, near Turin in northwestern Italy, had several poisoned cows die suddenly from acute hydrocyanic acid poisoning on August 6, according to the local animal welfare body IZS. The cattle were of the Piemontese breed.
The hydrocyanic acid comes from dhurrin, which is naturally present in young sorghum plants, although not in concentrations as high as those found in the field samples.
How did these cows get poisoned?
“We suspect that the drought caused this very high amount of dhurrin in the sorghum plants,” said Stefano Giantin, a veterinarian at the Istituto Zooprofilattico Sperimentale (IZS) for northwestern Italy, who is handling the case.
In normally growing plants, the amount of dhurrin decreases as the plants grow. But since the continued drought prevented the growth of the sorghum plants, the dhurrin concentrated inside them.
Hydrocyanic acid poisoning in cattle is rapid and brutal, with symptoms appearing 10-15 minutes after ingestion, death occurring after about 15-30 minutes. This poisoning causes respiratory, nervous and muscular disorders, writes Phys.org.
Dhurrin occurs naturally in sorghum, especially young shoots, which use it as a defense against herbivores, but when digested, it releases hydrocyanic acid, also known as hydrogen cyanide.
But “normally, it doesn’t cause death,” Giantin said.
Several farms were affected by the phenomenon
In samples taken from the farm in Sommariva del Bosco, the concentration of dhurrin in the shoots was at an unusually high level, which Giantin said appeared to be the result of the drought that hit Italy and much of Europe this summer.
The dose of hydrocyanic acid considered fatal for cattle is about 700 mg/kg; the animals at Sommariva were found to have amounts of over 900 mg/kg in their blood.
The only way to save the affected cows is to inject them with sodium thiosulphate, to neutralize the hydrogen cyanide.
In this way, the experts managed to save around 30 cows on August 11, when three other farms in Piedmont were hit by the same phenomenon, although not before another 14 died.