394 POISONING OF CATTLE BY FEEDING ON PASPALUM DILATATUM 



Outbreaks which have been reported were limited to the mid- 

 lands. No cases were reported from the northern portion 

 adjacent to the Drakensberg range or from the coastal belt. 

 In the latter area, however, this is understood as, owing to the 

 absence of frosts and to the humid conditions which exist for 

 the greater part of the year natural grazing is plentiful, and 

 the necessity for providing additional grazing during the winter 

 months, when the veld grazing is scanty, is not so important. 

 Paspalum has only been cultivated to a limited extent in this 

 area. In the midlands the cultivation of Paspdum had been 

 undertaken on a fairly extensive scale in former years, and in 

 seasons which favour the growth of the fungus it is almost 

 impossible to find an area under this grass which is not grossly 

 infected. Even along the roadsides, where accidentally sown 

 plants are to be found, these are almost constantly found to be 

 infested. 



Occurrence. 



The occurrence of the condition among cattle feeding on 

 Paspalum lands varies each year, and is chiefly dependent on 

 the extent to which the grass is infected. Like most fungi, 

 warm humid conditions favour development and dissemination, 

 and so, as is to be expected, the percentage of infected Paspalum 

 heads in a pasture is very much greater in seasons where a mild 

 winter is followed by frequent rains during the spring and early 

 summer. The stage of growth at which the fungus is able to 

 set up the characteristic symptoms is limited to the period when 

 the sclerotia are ripe, which coincides with the ripening of the 

 grass seeds. During the " honey-dew '' period the cattle appear 

 to be able to eat the infected grass with impunity. It was noted 

 that cattle feeding on Paspalum on which ripe sclerotia were 

 present evinced a special fondness for the high-standing diseased 

 heads after a meal of the lower and more succulent foliage had 

 been collected. This point has also been commented upon by 

 Brown and Ranck. Symptoms are usually developed about a 

 week after exposure in the infected pasture, and the percentage 

 of animals which show clinical symptoms varied froni 5 to 60 

 per cent, in the outbreaks investigated. 



Animals Affected. 



The condition was only noted to occur in cattle, and young 

 stock of from 14 months to two years appeared to be more 

 susceptible than adult cattle. Horses, donkeys, sheep and goats 

 grazed on the infected grass without developing any clinical 

 symptoms. This apparent immunity may to some extent be due 

 to the different method of grazing which is adopted by these 

 animals, by which little of the infected heads would be collected. 

 No fondness for diseased heads such as was observed in cattle 

 was noted in these animals. 



