[affected.gif] Animals most affected
Cattle.


[etiology.gif] Etiology
Poisoning by straw treated with ammonia either in a digester or under plastic sheets (to increase the non-protein nitrogen and the digestibility of the straw or to aid storage). Occurs through:


[toxic.gif] Toxicity
Direct transfer of ammonia across the alimentary tract and rumen, causing hyperammoniaemia and an alkalosis. Increase in lactacidaemia leading to a possibly fatal acidosis.
Fasting, an abrupt change of diet, a low water intake or lack of water all increase the likelihood of poisoning. A diet based on concentrates reduces the severity of the poisoning.
Note:frequently with poorly treated straw (i.e. when kept under cover), the conditions encourage the growth of fungi responsible for producing mycotoxins.
Toxic doses vary according to the level of protein in the feed:
TD cattle where protein > 12% and
    soluble nitrogen > 60%


[clinical.gif] Clinical features
Peracute state
Rapidly fatal (within minutes) and without any clinical signs.

Acute form
Predominantly neurological, with:

Sub-acute form
(Predominantly gastrointestinal):


[lesions.gif] Lesions
Non-specific:


[treatm~1.gif] Treatment
If large quantities are ingested:
Acute state

Sub-acute state


[labinv~1.gif] Laboratory investigations
The toxic components break down and disappear rapidly: