The Piedmontese cattle on the farm in Sommariva del Bosco, near Turin in northwest Italy, died suddenly due to acute prussic acid poisoning on August 6, according to the local IZS animal welfare body.
This acid comes from dhurrin, which is naturally present in young sorghum plants, although not in the same high concentrations as those found in samples taken at the site.
"We suspect that the drought caused this very large quantity of dhurrin within the sorghum plants," said Stefano Giantin, a vet at the Istituto Zooprofilattico Sperimentale for northwest Italy, who is on the case.
With normal growing plants, the amount of dhurrin would lower as the plants grew larger. But since the ongoing drought has stunted the growth of sorghum plants, dhurrin has concentrated inside them.