138 Journal of the Department oi' AoRictTLTURE. 



POISONING OF CATTLE BY FEEDING ON OLD 

 MEALIE LANDS. 



By D. T. Mitchell, M.R.C.V.S., Acting' Director of Veieriuary 

 Research, Veterinary Researcli Laboratory, Onderstepoort. 



During recent years, in various parts of Natal, a number of cases 

 of paralysis in cattle ha^e occurred wlien the animals have been 

 allowed access to uiealie lands for grazing purposes in the latter 

 part of the winter. 



It is customary in Natal, when harvesting mealies, to discard 

 all badly formed cobs, which are either left on the stalk or dropped 

 on the ground. In this way, when catfJe are changed to old lands, 

 there are lying* around considerable numbers of old and damaged 

 cobs which have been exposed to the weather for some months, and 

 these are readily eaten by the cattle. Owing to this, and to the 

 fact that ihe cobs are found in many of the districts in a very 

 mouldy condition, it has been suspected by farmers, in areas where 

 the paralysis among* cattle occurs, that this condition is due to cattle 

 eating a large quantity of these diseased mealies. Positive experi- 

 mental evidence on the subject was, however, lacking. Feeding tests 

 carried out at the Veterinary Research Laboratory, Pretoria, witli 

 material (mealies on cob) obtained in the Ixopo Division, Natal, 

 failed to give any positive results. The animals used in these experi- 

 ments were two sheep, two goats, one calf, and one mule. The 

 experiments were continued for three weeks, during Avhich time the 

 calf, sheep, and goats received an average total of 33 lb. of cobs 

 pel' week, and the mule 15.5 lb. per week. 



During the last five weeks of the tests soaked mealies were given. 

 One heifer was fed on a culture of the fungus grown on crushed 

 maize from one to one-and-a-half months; this animal consumed 

 23 lb. of this material between 19th and 31st March. No symptoms 

 other than a slight loss of weight could be observed in any of the 

 animals under observation. 



From the subsequent experiments on Diplodia-infected maize it 

 would appear that the quantities fed at Pretoria were too small to 

 produce effects, or, what is more probable, that the supply of cobs 

 forwarded, for experiment contained only a small percentage of 

 infected grains. 



Reference to these experiments will be found in a pamphlet* 

 published by Dr. Van der Byl, of the Division of Plant Pathology. 



This pamphlet gives a detailed description of Diplodia zea, with 

 photographs of infected maize cobs, and shonld be consulted by those 

 interested in the feeding tests referred to herein. 



*" Preliminary Investigation of the Deterioration of Maize infected with D'ljiUulia Zeae 

 (Schw.) Lev." from the Transactions of the Royal Soceity of South Africa, Vol, IV, Part 3, 

 1915. 



