In a normal growing year, nitrogen provides amino acids which produce protein in crops. During a dry year, nitrogen can be taken up by plants, but stalls before making the conversion from amino acids to proteins. This can leave heavy concentrations of nitrates in the stalk and make drought damaged corn potentially dangerous fodder for silage.
Iowa State University's Steve Ensley says, "The nitrate level can be high enough in stunted plants that if harvested as silage the nitrate can be toxic to livestock that consume the silage."
Experts advise caution. "Producers have several options to help determine whether nitrate toxicity might be a problem", Ensley continued. Iowa State Extension beef and dairy specialists can administer screenings of affected plants, and local veterinarians can forward silage samples for laboratory analysis. Producers who intend to use stunted drought year crops for silage would be wise to have that silage tested before making it part of a feeding program.
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