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Cows Will Consume Fertilizer

Cattle are inquisitive creatures. If they encounter something unusual or different, they will investigate. Behaviors of smelling and tasting are what they do to figure out what the material is. One product they will consume is fertilizer. A spill on pasture or hay land, or from a leaking granary can kill.

When animals find fertilizer laying on the ground, they will consume large amounts in a short period of time. For example, when urea is consumed, it is broken down into ammonia. The excess ammonia not used to form amino acids or detoxified in the liver, can cause Bovine Bonkers which can cause death in a short period of time. Consumption of 250 grams of urea can cause death.

In consultation with a livestock nutritionist, feed grade urea, (46-0-0) fertilizer can be included in rations. When combined with carbohydrate, keto acids are produced which are then converted into amino acids. When amounts added to a ration are controlled and mixed into silage as part of a total mixed ration or into a grain mix; problems are rare.

Ammonium nitrate (34-0-0) is broken down in the rumen. In two steps, the nitrate is converted to nitrite and then to ammonia. Accumulation of nitrite in the rumen and bloodstream can cause nitrate poisoning. The blood cannot release carbon dioxide in the lungs therefore reducing oxygen carrying capacity. It is commonly called nitrate poisoning when in fact, it is the nitrite form that causes the problem. Consumption of 1100 grams of ammonium nitrate can cause death.

Sulfur containing fertilizer such as ammonium sulfate (21-0-0-24) or elemental sulfur (0-0-0-90) is broken down in the rumen and incorporated into sulfur containing amino acids or excreted in the urine. Excess intake causes hydrogen sulfide to form. One theory is that hydrogen sulfide accumulates at the top of the rumen and crosses the rumen wall into the lungs. This interferes with oxygen transport in the blood and can cause polio. The second theory is that the sulfur reduces rumen pH and in turn this reduces the thiamine producing bacteria and the amount of thiamine available to the brain. In both cases, polio is a concern. Consumption of 40 grams of ammonium sulfate can cause death.

Care is needed when spreading fertilizer on pastures, stubble land, or areas where cattle have access. Spills, or fertilizer prills laying on the top of the soil can cause health issues or death in cattle.

For additional information, contact Barry at 403-741-6032 or


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