In addition to heat stress, and potential shortages of forage and water, hot, dry, weather can have other negative effects on livestock that can be much more severe. The likelihood of problems from three potentially deadly threats: blue green algae, nitrates, and prussic acid all increase because of hot, dry weather.
Nitrates can be a problem in crops such as corn, sorghum, canola, cereal grains and some grasses during exposure to drought. The aforementioned crops take up more nitrates than they use during poor growing conditions, resulting in a potentially toxic accumulation of nitrates in the lower portion of affected plants. The ingestion of high nitrate feedstuffs by animals can reduce the ability of the blood, of affected animals to carry oxygen, causing asphyxiation.
Prussic acid poisoning is caused by cyanide production in forage sorghums, grain sorghums, sudangrass and johnsongrass. Unfortunately, for livestock producers the symptom of prussic acid poisoning is often rapid death of the animal. Lush regrowth after stress has the most potential to have excess levels of prussic acid.