Description    Ionophores including monensin, salinomycn, narasin and lasalocid are added to some livestock feed. Overdosing can cause toxicosis in young and adult ruminants. Signs can develop immediately or over the course of a week or more. Death losses have continued for up to a month following exposure. The toxicity is primarily due to cardiac failure secondary to degeneration and necrosis in myocardial and skeletal muscle cells. Serum enzymes of muscle origin are elevated.
Species   Bovine, Caprine, Ovine
Signs   Abnormal lung or pleural sounds, Abnormal proprioceptive positioning, Agalactia, Anorexia, Arrhythmia, Ataxia, Back spasms, Blindness, Colic, Decreased, muffled, lung sounds, Dehydration, Diarrhea, Dull areas on percussion of chest, thorax, Dullness, Dysmetria, Dyspnea, Excessive salivation, First degree atrioventricular heart block, Forelimb lameness, Forelimb spasms, Generalized lameness or stiffness, Generalized weakness, Head, face, ears, jaw, nose, nasal, swelling, Head, face, neck spasms, Hemoglobinuria or myoglobinuria, Hindlimb lameness, Hindlimb spasms, Hyperesthesia, Inability to stand, Increased respiratory rate, Mucoid nasal discharge, Opisthotonus, Paraparesis, Peripheral venous distention, Pica, Reluctant to move, Rumen hypomotility or atony, Skin edema, Sudden death, Sweating, Tachycardia, Tongue protrusion, Tongue weakness, Trembling, Tremor
References   Puschner B. Serum, milk, and tissue monensin concentrations in cattle with adequate and potentially toxic dietary levels of monensin: pharmacokinetics and diagnostic interpretation. J Vet Pharmacol Therap 2016;39:363 [Web Reference]
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