Production Animal Clinical Toxicology

Aetiology | Epidemiology | Pathogenesis | Clinical Signs | Clinical Pathology | Necropsy | Treatment | Control

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Aetiology

Claviceps purpura - ergot of rye

Epidemiology

• seen in beef and dairy cattle during summer
• animals fed ergot contaminated grains
• grains poor quality and are contaminated by rye grass seed and ergot
• some pasture-fed animals can also be affected

Pathogenesis

• alkaloids responsible unknown
• may be the same as those that cause gangrene, but may be different, a response to differing climatic/environmental conditions
• possible that peripheral vasoconstriction does occur but not sufficient enough to cause gangrene
• as cattle may thermoregulate through peripheral circulation, the result is increased body temperature, and alternative mechanisms to control temperature become necessary

Clinical Signs

• milk production drop; reduced weight gain
• inappetence
• high environmental temperature results in elevated body temperature
• animals seek shade or sit in dams or creeks
• respiration rate increases especially after exercis
e
• salivate
• recover when stopped being fed ergot-contaminated feed

Clinical Pathology

• nonspecific

Necropsy

• nonspecific

Treatment

• removal of contaminated feed

Control

• monitor quality of grain
• avoid grazing of ergot-affected rye grass