Caution urged when feeding out drought affected sorghum crops

Prussic acid in sorghum can kill cattle if not managed properly. That’s the message market leaders in forage and grain sorghum seed, Pacific Seeds want to get out there.

The reason behind this announcement is an increase in requests for information the company has received about prussic acid poisoning and management, due in part to growers baling failed grain sorghum crops for hay.

The company’s recently appointed Summer Grains Agronomist, Trevor Philp said that while failed sorghum can offer a valuable part of the feed ration for cattle producers in these dry times, any feed from this source should be tested for prussic acid levels.

“Prussic acid is found in all sorghum varieties and grain sorghum generally has considerably higher levels than forage sorghums.”

“Levels of Prussic Acid at or below 600 parts per million are safe for cattle, however in feed tests that have been conducted on some drought affected grain sorghum hay,levels of 3000 ppm have beendetected which in anyone’s book will cause problems.”

According to Mr Philp, the younger a sorghum, the higher the prussic acid levels.

“This problem can be compounded if the sorghum is stressed in the growing phase.”

“As a general rule of thumb, if the parent crop is too risky to feed, the hay made from that crop will also be too risky to feed.”

As part of a management plan, if it’s not feasible to do a feed test farmers should introduce stock to the sorghum slowly and observe them for signs of prussic acid poisoning in the first 24 hours. Additionally it is important to provide stock with sulphur licks as this helps break down the toxin. However if hungry cattle gorge on fodder that is high in prussic acid, toxic levels of this compound are formed at too rapid a rate to be detoxified and deaths will occur.

“I guess message for growers to note is that while baled sorghum can be a very handy feed option in tight times, such as we’re now experiencing, it’s important to know what to look for as far as prussic acid is concerned and how to manage it,” Mr Philp said.

Symptoms of poisoning include muscle trembling, staggers, deep and rapid breathing, frothing at the mouth and gasping.

“To borrow a phrase from the government; be alert, not alarmed.”