DISTRIBUTION:
• Mainly utilized as a pasture or a lawn grass, but it also escapes and grows in moist fertile places in the wild.
• It grows naturally in the highlands of Kenya, Uganda, Tanzania, DRC, Ethiopia, Rwanda and Burundi.
• It has been introduced to many other parts of the world.
BOTANICAL DESCRIPTION:
General: This is a dense mat-forming perennial grass that has both stolons and creeping rhizomes.
Leaves: Leaf blades are flat, folded or rolled with a prominent midrib and leaf sheaths are overlapping.
Flowers: During the flowering season (August - April) long white filaments can be seen, but there are no visible inflorescences.
TOXIC PRINCIPLE:
• Grass invaded with Spodoptera exempta (army worms, kommandowurms).
• The worms themselves are not toxic and the kikuyu grass in itself appears to be non-toxic, but a combination of these two results in toxicity through an unknown mechanism.
• It takes ±10 days for the grass to become toxic after an army worm infestation and the toxicity is retained for 4 - 6 weeks after the worms have gone (life-cycle is completed, or they are killed by insecticides).
Rumenitis can also occur when the grass was not previously invaded by army worms, but when there was a growth spurt during hot weather, following high nitrogen fertilization and irrigation of kikuyu.
SYSTEMS AFFECTED:
Gastro-intestinal system.
CLINICAL SIGNS:
Latent period of 24 hours or longer.
1. Gastrointestinal signs:
• Ruminal atony and tympany.
• Colic: Grunting and kicking at the abdomen
• Usually a constipation.
• Ruminal irritation results in an excess accumulation of fluids, sloppy ruminal contents which may gush from the mouth and nose at death.
• It also results in severe dehydration with sunken eyes and a unpliable skin.
2. Neuromuscular signs:
• Bulbar paralysis (“shamdrinking” and severe salivation due to inability to swallow).
• Muscle tremors• Ataxia, the animal lies down and rises with difficulty.
Dies 2 - 4 days later. Most deaths within 48 hours.
NECROPSY:
Macroscopical findings:
• Excess and severely fluid ruminal contents (bright green).
• Hyperaemia and large necrotic areas of the forestomach mucosa.
• Severe dehydration.
HISTOPATHOLOGY:
Non specific.
TREATMENT:
• Symptomatic and supportive.
• A high percentage of affected animals die.
PREVENTION AND CONTROL:
• Prevent infestation of pasture.
• Control worms with pesticides.
• Withdraw animals from pasture for at least 40 days from last army worm presence.
• Test for toxicity by using less valuable tracer cattle for four days prior to allowing rest of herd back onto pasture.
