•276 A -lU'K-HKSISTANT CONDITION IN CATTLE 



Mr. A. K. Henderson in an interview (November, 

 1015), stated that Avlien fanning on the Blackall Range 

 several yt^ars previously he had had some experience with 

 tick resistant stock. He had vaccinated nine cows with 

 " a gnmmy substance '' found exuding from one tick-free 

 animal. Mr. Henderson had destroyed his records on sell- 

 ing the farm and could only give the results from memory. 

 In about a Aveek the first effect was noted, spreading slowly 

 from the point of vaccination and taking some weeks to 

 reach the shoulder. Of the nine treated, six " took " and 

 -from being tick-carriers they all had ver}'^ few ticks. These 

 -cows were sometimes dipped with the rest. One cow, 

 which Mr. Henderson retained on selling the farm and after- 

 wards disposed of, became ticky some three years after 

 -treatment. From the slowness with which the effects of 

 vaccination spread Mr. Henderson had formed the opinion 

 it was not distributed through the blood but through the 

 lymph. (See also R.S.C, 1915). 



Mr. T. S. Rowbotham, of Springbrook plateau (on 

 the N.S.W. border), who has a herd of about 90 smooth- 

 skinned animals, chiefly Jerseys, informed us that he had 

 found only three mature ticks during the 1917-18 tick 

 season though he had milked 43 cows twice daily, the 

 remainder being regularly yarded and examined for ticks 

 but -without further finds. No sign of tick irritation was 

 ■observed. The greatest number of mature ticks collected 

 by him during any one season since 1914 was six. 



At the other end of the narrow horse slioe-like plateau 

 redwater made its appearance each year. In May, 1914, 

 he introduced 21 tick infested cattle into his property, 

 16 ))eing dipped Avhile the remaining five were left untreated 

 in the hope that they might be the means of disseminating 

 ticks and keep up an *' immunity " from fever. The result 

 was not successful as far as tick infestation was concerned. 



()ti another occasion, May, 1917, he moved some of his 

 herd to a neighbouring paddock where ticks soon appeared 

 on the cattle, a number contracting tick fever and some djdng 

 in spite of several weekly washings in order to control the 

 infestation. No subsequent treatment had been resorted 

 to and the animals remained clean except for the jiresence 

 of young ticks which however did not mature. He reported 



