'Kisieblaar' Malva Parviflora

1. Poisoning

‘Kisieblaar’ (Malva parviflora) is considered poisonous due to it containing thiaminases, but has always been considered of academic interest only.

However a suspected case (not confirmed) occurred after Angora goats which were Kraaled and ate a significant amount of ‘kisieblaar’ over a day. This occurred in May after very good autumn rains and a profuse growth of Kisieblaar in the kraal as in photo below and was it was also growing in many areas on the farm. No other significant plants were present in the kraal and the kisieblaar covered the ground as in the photo. The goats were not treated but put through water dip to clean which contained Zinc sulphate (1kg/1000litres) prior to this. It had rained and goats wet overnight.

Usually thiaminases would be expected to take a couple of weeks to cause clinical signs which did not fit this clinical picture but polioencephalomalacia has been reported as acute and subacute.

Symptoms:

When the Angora goats were chased out neurological clinical signs developed and reported by farmer as. 3-5% were affected

• Ataxia (unsteady)
• Some goats lay down and could not stand. 2 goats went into lateral decumbency but rest held their heads up and were responsive.
• Tremors

Treatment

• Farmer was immediately advised not to chase goats
• Activated charcoal (2mg/kg) was dosed as a tablet form and water dosed to those with clinical signs.
• Vitamin B was injected
• Lucerne hay provided

The next day all the Angora goats were able to stand and clinical signs disappeared. No deaths occurred in order to take samples for histopathology confirmation.

What do the thiaminases cause?

The softening of the brain (laminar necrosis of the cerebral cortex) is through hypoxia (lack of oxygen) due to substances that block thiamine which is essential to neuronal carbohydrate metabolism.