DISTRIBUTION:
It is widely distributed in the Karoo on a variety of soil types, ecxept in brackish areas, where it does not flourish.
BOTANICAL DESCRIPTION:
General: A soft, dense, perennial woody shrublet about 100 - 600 mm high with a rounded form, 60 - 400 mm in diameter. It is an extremely active invader, which flourishes on overgrazed veld.
Leaves: The numerous hairless leaves are small, narrowly linear, somewhat sticky and arranged alternately on the stems. They taste bitter, hence the common name.
Flowers: At the end of almost every branchlet there is a small yellow flower head. It is ±10 mm in diameter and without ray florets.
TOXIC PRINCIPLE:
Valsiekte
• An unidentified toxin
Kaalsiekte
• Nursing lambs/kids: An unidentified toxin is excreted in the milk of ewes and affects the suckling lamb/kid.
Lakseersiekte
• Sheep or cattle which ingest large amounts of bitterbush develop diarrhoea.
SYNDROMES:
Valsiekte, Kaalsiekte, Lakseersiekte.
SYSTEMS AFFECTED:
Central nervous and gastro-intestinal systems, as well as skin and appendages.
CLINICAL SIGNS:
• Dorpers and Dorper-crosses are susceptible to Valsiekte. (Merino’s don’t eat the plant).
• 2 - 4 month old lambs are affected.
• Ataxia of hindquarters, paresis.
• Diarrhoea and alopecia simultaneously contracted.
Kaalsiekte is a problem in sheep lambs and goat kids less than 3 weeks of age when the mothers graze on the bitter bush and ingest large amounts, usually unpalatable.
• Problem seen after good rains if the bitter bush is plentiful, young and succulent.
• Lamb/kid is born with a normal coat.
• The toxin is excreted in milk.
• From 3 - 14 days old (after 3 weeks not a problem anymore) pruritus, the pulling out of fleece or hair and alopecia (especially over the rump, shoulders and trunk) are noticed.
• Usually only the non-pigmented parts are affected.
• Wool/hair remains on the limbs and head.
• Complications:
- Exposure - sun burnt during the hot, sunny days.
- Evenings very cold - hypothermia, pneumonia.
Sheep and cattle suffering from Lakseersiekte may die suddenly or develop a persistent, sometimes haemorrhagic diarrhoea, which leads to weakness, dehydration and recumbency.
NECROPSY:
Valsiekte:
• Status spongiosus of spinal cord
Lakseersiekte:
• Severe gastroenteritis - even haemorrhagic.
• Ulcerative lesions.
TREATMENT:
Valsiekte:
• No specific treatment
Kaalsiekte:
• Protect against the sun during the day and extreme cold during night.
• Lanolin and other emollients on the skin.
Lakseersiekte:
• Remove immediately and treat symptomatically.• Sheep: Fluid and electrolyte replacement.
