Nitrate toxicity in cattle

Authors: Visser R, Vermunt J
Publication: New Zealand Veterinary Journal, Volume 35, Issue 8, pp 136-137, Aug 1987
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Toxicology, Poisoning - plant, Poisoning - chemical
Article class: Correspondence

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Abstract: Nitrate poisoning can be a problem in livestock, but occurs commonly in cattle. High levels of nitrate and nitrite in plants and water sources are the primary cause of acute nitrate poisoning in cattle. Groundwater may accumulate toxic levels of nitrate by leaching from effluent, or soils heavily fertilised with nitrogen. Plants are the main source of nitrates to cattle. These include second-growth of rape, choumollier and turnips, immature green oats, Italian ryegrass and young maize. Rapidly growing plants, after a period of stunting (as for example, caused by drought), grown in rich nitrogenous soils are most dangerous. Nitrate poisoning in cattle is due either to ingestion of preformed nitrite, or to the conversion of nitrate to nitrite in the rumen by micro-organisms. Ruminants are more susceptible to nitrate poisoning than monogastric animals because the rumen microflora readily convert nitrate to nitrite in the reduction process of forming bacterial protein. The quantity of nitrate that will cause poisoning is variable and depends on: a) the rate of nitrate consumption, b) the type of feed, c) the amount of carbohydrate in the feed, and d) the stage of adaption to nitrate in the diet. Poisoning is not so much due to the actual quantity ingested as the rate at which it is consumed. Toxic levels of nitrate lead to a rapid build-up of nitrite in the rumen…

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