FACT SHEET 6 - NITRATES
Nitrate Poisoning
Cause
If animals eat too much feed that is high in nitrates which have not been changed to protein in
the plant, is a common cause of Nitrate poisoning, It can also be caused by animals eating too
much urea or nitrogen fertilizer that has been dropped in the field or accessible to animals who
then eat it. Nitrate fertilizer is palatable, particularly to cattle.
High Nitrates in Feed
Cause
 All plants contain nitrate, however feed grown under stressful conditions can cause
excessively high levels.
 Most weeds, commonly found in corn can accumulate toxic levels of nitrate
 Nitrates accumulate in plants only when either the soil has large amounts of nitrate or
factors interfere with the normal plant growth.
 Nitrogen fertilization and drought most common factors in nitrate build up.
 Nitrate building up increases with a delay in applying fertilization.
 Nitrates absorbed by plant roots from the soil are applied to the plant tissue as amino
acids, proteins and nitrogenous compounds. The main area for converting nitrates is in
the growing leaves. In bad conditions, i.e. drought, the conversion process is affected
causing the nitrate to build up in the stalk and stems.
 Not all droughts cause high nitrate levels in the plants. Plant roots will not be able to
absorb nitrates if supply of soil nitrate is in the dry soil surface.
Nitrate Toxicity in Animals





Ruminant animals use nitrogen in nitrates to make protein. The exchange is made by
bacteria in the rumen
Nitrate toxicity occurs when the feed is high in nitrate and overwhelms the animals’
digestive system. Nitrate builds up and absorbs into the bloodstream changing to a form
(met hemoglobin) which cannot carry oxygen to the lungs and body tissue. The animal
suffocates.
Toxicity levels depend on how much and also how fast the nitrate was taken.
Symptoms of nitrate poisoning come on suddenly. Difficult in breathing, rapid weak
heartbeat, below average body temperature, loss of muscle coordination. Also brownish
coloring to the blood. Usual cases death occurs within 3-4hours.
Chronic nitrate poisoning can cause reproductive problems, including abortions.
Source: University of Merryland, USA