Establishment of the Toxic Level of Nitrofurazone for Young Liquid-Fed Calves

Abstract

Fifty male Holstein-Friesian calves with mean live weight of 44.5 ± 1.68 kg were fed 8 dosage rates of nitrofurazone in a high-fat milk replacer with or without 1.27 mg thiamine hydrochloride per kilogram of liquid diet for six weeks. Paralysis of the limbs occurred in all calves within a few days when the nitrofurazone dose provided 30.7 mg/kg live weight. At a daily mean intake of 13.9 mg/kg live weight, 4 of 5 calves showed hyperirritability and convulsions after three to five weeks, and milk replacer intake and growth rate were depressed. A lower intake (7.1 mg/kg live weight) produced a borderline reduction in milk replacer intake but caused no apparent nervous disorders. Removal of the drug from the diet after six weeks resulted in no differences due to previous drug treatments in growth rate or milk replacer intake of surviving calves during a 28-day post-treatment period. Thiamine supplementation had no effect on the onset of nervous signs or on growth rate and milk replacer intake. Plasma glucose, lactate, pyruvate, and magnesium appeared generally unrelated to the drug effects. © 1970, American Dairy Science Association. All rights reserved.