Abstract 439

Radunz,-BL; Wilson,-G; Beere,-G

Technote. 1983, No. 30, 3pp.; 5 ref.; mimeographed.

Rubberbush (Calotropis procera) is a coarse shrub naturalized in some parts of Australia. Two sheep fed on cracked rice and chaffed legume hay were given hammermilled fresh leaf of C. procera 5 g/kg bodyweight for 30 days and 10 g/kg for another 30 days. For the first 2 weeks the leaf was given by stomach tube but in the last 6 weeks the sheep ate it readily. Eight castrated cattle 10 to 12 months old were fed on ground rice and chaffed legume hay and given free access to pasture hay. Groups of 2 cattle had no C. procera or they were given the milled leaf 2, 5 or 10 g/kg bodyweight for 84 days, i.e., 10, 20 or 40% of diet excluding hay; they ate it readily. There was no clinical or gross pathological sign of poisoning and no histological sign in liver or kidneys of sheep or cattle. Some cattle, including those not given C. procera, had mild megalocytosis and upper nephron nephrosis. Cattle given no C, procera gained bodyweight 20 or 22 kg; those given increasing amounts gained 19 or 23, 11 or 18, and 18 or 28 kg. The small size of the sample did not allow a conclusion on the animal production potential of C. procera. Present results indicated that in the wet season of northern Australia C. procera was not toxic in the same doses that caused acute poisoning elsewhere. It was postulated that either the toxin was not present in the northern Australia variety or that local conditions did not favour the production of the toxin. C. procera may be a suitable material for a potential wood alcohol industry, and the leaves as a byproduct could provide a protein supplement for cattle in the dry season.