Veterinary problems with ammonia-treated
There are four reasons for adding ammonia to cattle forages:
- Treatment of lower quality forages with ammonia reduces the
amount of indigestible lignin in the feed thus increasing feed
digestibility (and quality) - useful for straw and poor quality
- Ammonia is a non-protein nitrogen source that rumen
micro-organisms can use to make microbial protein. Adding ammonia
to feed effectively increases its crude protein content.
- Adding ammonia to whole crop silage can reduce the breakdown of
true protein during the fermentation process, again increasing the
quality of the end product
- Adding ammonia inhibits mould - useful for wet hay
However if ammonia is used to treat relatively high sugar
forages then problems can result with cattle showing nervous signs.
The condition is often described as "bovine bonkers". The most
likely cause of the problem are imidazoles, which are by products
of the reaction between ammonia and plant sugars
The signs are usually seen within hours of eating the
ammonia-treated feed. The higher the dose the faster the signs
- Hyper excitability is the primary sign - restlessness,
- Affected cattle run in circles, collide with inanimate objects
and may stampede.
- Frequent urination and defaecation
- Sweating and fever
- Unsteady gait
- Muscle tremors including ear twitching
Signs usually last for around 5 minutes and may be repeated at
20 -30 minute intervals. During these intervals affected animals
will resume eating and show no signs. Signs have also been
reported in calves nursing cows eating ammoniated forages but this
is not a consistent finding
The clinical signs are very useful particularly in conjunction
with access to ammonia-treated forages.
However, there are no definitive tests so the diagnosis has to
Get veterinary advice as soon as possible to rule out other
causes of nervous disease.
No treatment has been found
Remove the source of ammonia
Roughage containing high levels of reduced sugars, including
grass and whole crop feeds, should not be treated with ammonia, nor
should forages that are already mouldy.
High levels of moisture in the forage and high environmental
temperatures predispose to the production of the toxin so avoid
treating wet forages with ammonia particularly in summer. Also
ensure that the percentage of ammonia is less than 3%.