TOXICOLOGY OF NITRATES AND NITRITES IN LIVESTOCK

Summer droughts and harsh winters, associated with excessive applicati on of nitrogenous fertilizers, have caused an increased incidence of n itrate poisoning in cattle. Such poisoning is common in livestock that are raised in the western Great Plains of North America. Abortion and sudden death in cattle that consume a high level of dietary nitrate c an lead to severe financial losses for producers. Experimental studies and field reports have incriminated chronic sublethal nitrate poisoni ng as a causal or contributing factor in various clinical manifestatio ns (e.g., reproductive problems, interference with iodine and vitamin A metabolism, and reduced growth and production); however, these disor ders do not necessarily occur in every animal or herd or on every farm where high-nitrate forages are used. Diagnosing nitrate poisoning is a common challenge in bovine practice. This article describes the pred isposing environmental factors, pharmacokinetics, mechanism of action, clinical signs, diagnosis, and treatment of nitrate poisoning in live stock.