Production Animal Clinical Toxicology

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

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Plants

Lantana camara

Epidemiology

animal factors

• cattle (especially young), sheep and goats susceptible although sheep are generally not kept where lantana is found
• horses may be susceptible
• newly introduced naive stock
• plants may be more palatable to some stock than others
• reduced access to alternative feed sources

plant/environmental factors

• toxicity primarily related to plant genotype and not other factors
• generally all red flowered varieties toxic
• pink flowered in N. Queensland toxic
• but can have exceptions

Pathogenesis

• lantadene A and lantadene B (triterpene acids)
• metabolised in liver and cause damage to bile canaliculi membrane
• cholestasis, retention of bilirubin, phylloerythrin and exacerbation of ruminal stasis

Clinical Signs

• signs can appear after one feed and within 24 hr
• early
• depression, inappetence
• constipation, diarrhoea in severe cases
• frequent urination
• photosensitisation and icterus develop in 2-3 days
• photophobia
• reddening, inflammation of pale skin
• reddening, swelling, ulceration of nostrils, gums
• swelling of ears
• lacrimation, swelling of eyelids
• extensive necrosis of skin, even to loss of horns and hooves
• acute cases, death in 2 days
• chronic cases, death 1-3 weeks primarily due to
starvation
• dehydration
• hepatic and renal damage
• severe photodynamic, dermatitis
• intercurrent infection

Clinical Pathology

• hepatic enzymes; bilirubin to determine if icterus due to cholestasis
• only an adjunct to clinical observation

Necropsy

• icterus
• dehydration
• rumen contents dry; faecal masses dry and mucoid covered in large intestine
• swollen ochre coloured liver; necrosis generally not evident
• swollen gall bladder
• kidneys - pale to yellowish which may develop a greenish colouration on exposure to air
• acute cases: haemorrhagic gastroenteritis

Diagnosis

• history
• clinical signs

Treatment

• dose with activated charcoal, fluids
• supportive therapy

Control

• management, elimination of plants
• naive stock should be offered sufficient quantities of alternative feed