Production Animal Clinical Toxicology

Plants | Epidemiology | Pathogenesis | Clinical Signs | Clinical Pathology | Necropsy | Diagnosis | Treatment | Control

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Plants

• Rape, kale, turnips, cabbages - fodder crops in temperate climate
• Wild radishes, wild turnips, cresses

Epidemiology

• ruminants

Pathogenesis

• contain a number of potentially toxic compounds that can give rise to a complex of diseases
• goitrogens
• nitrates
• amino acid - S-methylcysteine sulphoxide (SMCO) which, when metabolised by ruminal microbes to dimethyl sulphide, causes haemolytic anaemia by precipitating Hb into Heinz bodies causing splenic removal of RBCs
• SMCO content increases with age of plants, flowers high content
• low intake induces low grade anaemia
• high intake induces acute haemolytic response

Clinical Signs

• loss of condition, drop in production
• jaundice; increased HR; anaemia
• diarrhoea
• effects most apparent with pregnant/recent calvers
• Hburia

Clinical Pathology

• macrocytic anaemia - presence of Heinz bodies

Necropsy

• jaundice
• dark kidneys
• Hburia

Diagnosis

• history
• clinical pathology
• necropsy

Treatment

• remove from pasture; supportive

Control

• grazing management; use of low SMCO containing varieties