Grows in fertile, damp soil, usually in the shade.
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.
• 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.
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.).
Identical to Geeldikkop - Clefts, etc. identical
• 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.
• 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.
Keep in shade. Diet low in chorophyll. Antihistamines. Corticosteroids. Cholagogues. Liver supportive treatment. Valuable animals – barrier creams and tattoo ink will protect from sunburn.
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.