Panicum species
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Date
Authors
Botha, C.J. (Christoffel Jacobus)
Venter, Elna
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Abstract
DISTRIBUTION:
Grows in fertile, damp soil, usually in the shade.
BOTANICAL DESCRIPTION: General: Annual or perennial tufted grass species growing from rhizomes. Leaves: Leaf sheath is often hairy and leaf blades are rolled. Flowers: Inflorescence is an open panicle and often flushed with purple when growing in direct sunlight. September - March.
TOXIC PRINCIPLE: • Similar to Geeldikkop. • Toxic principle: Steroidal saponins.
MECHANISM OF ACTION: • Hydrolysis of a steroidal saponin to diosgenin with subsequent hydrogenation, reduction and epimerisation, which occurs in the rumen. • Epismilagenin and episarsasapogenin amongst others, are formed, absorbed and conjugated with glucuronic acid in the liver to be excreted via the bile. • However, the epismilagenin and episarsasapogenin glucuronides bind to Ca2+ to form an insoluble salt, which precipitates to form biliary crystals which obstruct the bile ducts.
SYNDROMES: Dikoor.
SYSTEMS AFFECTED: Liver.
CLINICAL SIGNS: Dikoor – similar to geeldikkop – distribution Free State and Highveld. Sheep condition mainly. Usually milder disease (probably due to farming practice – detected earlier and kept in shade etc.).
NECROPSY: Identical to Geeldikkop - Clefts, etc. identical Macroscopical findings: • Icterus and photosensitivity. • Liver - enlarged khaki to yellow-brown. • Chalky white sediment in bile ducts and gall bladder. • Later small pits on surface although morphology never distorted as in F.E. • Kidneys swollen and light in colour, with small green spots distributed through cortex.
HISTOPATHOLOGY: • Accumulation of crystalloid material in portal and intra- and extrahepatic bile ducts leading to partial or complete occlusion and concentric, lammellar periductal fibrosis. • Plate-like structures seen on section as clefts and on scanning EM as rose- like structures and/or debri in greater ducts. • Other pathological changes are present but are mostly secondary to this.
TREATMENT: Keep in shade. Diet low in chorophyll. Antihistamines. Corticosteroids. Cholagogues. Liver supportive treatment. Valuable animals – barrier creams and tattoo ink will protect from sunburn.
BOTANICAL DESCRIPTION: General: Annual or perennial tufted grass species growing from rhizomes. Leaves: Leaf sheath is often hairy and leaf blades are rolled. Flowers: Inflorescence is an open panicle and often flushed with purple when growing in direct sunlight. September - March.
TOXIC PRINCIPLE: • Similar to Geeldikkop. • Toxic principle: Steroidal saponins.
MECHANISM OF ACTION: • Hydrolysis of a steroidal saponin to diosgenin with subsequent hydrogenation, reduction and epimerisation, which occurs in the rumen. • Epismilagenin and episarsasapogenin amongst others, are formed, absorbed and conjugated with glucuronic acid in the liver to be excreted via the bile. • However, the epismilagenin and episarsasapogenin glucuronides bind to Ca2+ to form an insoluble salt, which precipitates to form biliary crystals which obstruct the bile ducts.
SYNDROMES: Dikoor.
SYSTEMS AFFECTED: Liver.
CLINICAL SIGNS: Dikoor – similar to geeldikkop – distribution Free State and Highveld. Sheep condition mainly. Usually milder disease (probably due to farming practice – detected earlier and kept in shade etc.).
NECROPSY: Identical to Geeldikkop - Clefts, etc. identical Macroscopical findings: • Icterus and photosensitivity. • Liver - enlarged khaki to yellow-brown. • Chalky white sediment in bile ducts and gall bladder. • Later small pits on surface although morphology never distorted as in F.E. • Kidneys swollen and light in colour, with small green spots distributed through cortex.
HISTOPATHOLOGY: • Accumulation of crystalloid material in portal and intra- and extrahepatic bile ducts leading to partial or complete occlusion and concentric, lammellar periductal fibrosis. • Plate-like structures seen on section as clefts and on scanning EM as rose- like structures and/or debri in greater ducts. • Other pathological changes are present but are mostly secondary to this.
TREATMENT: Keep in shade. Diet low in chorophyll. Antihistamines. Corticosteroids. Cholagogues. Liver supportive treatment. Valuable animals – barrier creams and tattoo ink will protect from sunburn.
Description
Colour photos. Final web-ready size: JPEG. Photo 1: 12.9 kb, 96 ppi; Photo 2: 23.7 kb, 72 ppi; Photo 3: 102 kb, 72 ppi; Photo 4: 26.5 kb, 96 ppi. Original TIFF file housed at the Dept. of Paraclinical Sciences, Section Pharmacology and Toxicology, University of Pretoria.
Keywords
Plant poisoning, Toxicology, Plant poisoning in animals, Poisonous plants, Dikoor, Saponins
Sustainable Development Goals
Citation
Botha, CJ & Venter, E 2002, 'Plants poisonous to livestock Southern Africa (CD-ROM)' University of Pretoria, Faculty of Veterinary Science, Dept. of Paraclinical Sciences, Section Pharmacology and Toxicology, Pretoria, South Africa.