270 A TICK-RESISTANT CONDITION IN CATTLK. 



female ticks were visible on the dipped ntock l)ut close 

 examination rev^ealed great numbers of small ticks. The 

 following are some of the cows carefully examined on these 

 occasions : — 



Melba. This cow was one inoculated as a calf from a 

 resistant animal. Another calf was treated at the same time 

 and became resistant : the latter died last year. Melba waa 

 tick-free when examined on January 25th, 1918, while 

 patches of exudate were visible. On February 5tli a few 

 larvae were seen and exudate was again present. 



Magpie, a calf of the first resistant cow owned by Mr. 

 F. Hull. She had never been dipped and was practically 

 free from ticks when examined on January 25th, 1918. 



Wendy, Shorthorn- Jersey grade ; this cow was fairly 

 free from ticks when examined on January 25th, 1918 ; 

 tiny scabs could be felt by passing the hand over the body. 

 When examined on Februar}" 5th a few small ticks were 

 visible while a certain lumpiness was evident on the 

 escutcheon. 



Daphne, a tick-free animal, was shewing dry scabs on 

 the escutcheon. This cow was dipped regularly in order 

 to ascertain if her resistant powers would be thereby 

 lessened. She was still tick-free in June, 1918. 



Bluebell II, dam. Bluebell I, was also examined on 

 January 2oth, 1918. This cow was ticky but the infestation 

 consisted mainly of small ticks and unengorged females. 



On February 3rd a visit was paid to Mr. Paton's dairy 

 farm, where over 40 cows were milking. He keeps his stock 

 free from ticks by rotation of paddocks and regular spray- 

 ing. Mr. Paton shewed two cows which never carried ticks. 

 Both were short-haired and of Ayrshire- Shorthorn cross. 

 One occasionally exhibits the exudate. Both are regularly 

 sprayed. 



On the same day we also visited Mr. Duke's dairy farm, 

 where there are 37 milking cows which are dipped regularly 

 every three weeks. One roan cow was pointed out as being 

 especially free from ticks. The remainder of the herd was 

 lightly infested. 



