Production Animal Clinical Toxicology

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Plants

Lupinus spp.

Aetiology

Phomopsis leptostromiformis, a saprophyte infecting Lupinus spp.

Epidemiology

animal factors

• can affect sheep, cattle, horses
• young sheep more likely to eat infested stem material and are more likely to develop illness
• some sheep will eat more stubble than others and will develop illness first
• high stocking rates, lack of access to alternative feed increases risk of disease

plant/environmental factors

• fungus grows localised on green stems during winter and spring
• extensive colonisation of plant at senescence
• toxin produced after plant dies when the fungus adapts to being a saprophyte
• may have increased toxicity in stubbles after rain or during periods of high humidity
• stubbles can be toxic for months or years
• seeds can be occasionally toxic

Pathogenesis

• toxins are polypeptides called phomopsins A, B, C
• cause progressive loss of hepatocyte microtubules which leads to abnormal mitosis, mitotic arrest, fat infiltration and cytotoxicity
• also disrupt enzyme systems within cell membranes

Clinical Signs

sheep

• acute - seen within 2 days of feeding stubble
• large proportion of flock affected
• lethargy, depression
• anorexia
• icterus
• chronic - seen over a period
• variable numbers within flock
• inappetence
• loss of condition
• lethargic and weak
• icterus not a feature; sclera are not normal white colour and may be congested
• photosensitisation is not a feature if green feed is not available
• chronic copper toxicity can be observed

cattle - 2 syndromes

• common - effects late pregnant/recently calved cows mainly during autumn
• sudden deaths
• abortion
• may be icteric and photosensitised
• less common - ill-thrift, few mortalities
• development of photosensitisation following season when green feed available

horses

• haemolytic anaemia associated with severe hepatic disease

Clinical Pathology

• hepatic enzymes, bilirubin

Necropsy

sheep

• acute
• icterus
• swollen liver, yellow to cream in colour
• enlarged gall bladder
• ascites, connective tissue oedema
• occasional cardiac, skeletal myopathy
• chronic
• misshapened, small hard coppery to tan liver

cattle

• common syndrome
• fatty liver, secondary ketosis due to inappetence at crucial stage
• less common
• firm fibrotic liver

Diagnosis

• history
• clinical signs
• necropsy

Treatment

• removal if at early stage

Control

• management with early detection of poor animals and removal of flock
• low stocking rates
• graze lupins soon after harvest and not autumn
• ensure access to lupin seed and non lupin material as well
• make hay by cutting green lupins just after flowering
• development of fungal resistant lupins