Cattle-Fever Ticks. 17 



on, with a drop of 2^ or 3 feet so that the arsenical bath will cover 

 the edge of the slide at least a foot in depth. This kind of slide 

 for dairy cows prevents bruising the udders. 



Slides should be finished vei-^' smooth by much floating of the 

 concrete and finishing with a mixture of equal parts of cement and 

 fine sand. 



Cover. — The vat should be so inclosed or covered as to keep chil- 

 dren or small animals from entering or falling in. 



Dripping chute and chute leading to the vat. — The dripping chute, 

 which is regarded as more satisfactory than a dripping pen, is built 

 at the head of the exit incline in line with the vat. It should be 

 about 30 inches wide. The length will depend on the number of 

 cattle to be accommodated at one time. From 4 to 5 feet are allowed 

 for each animal, and a length of from 20 to 40 feet is considered a 

 convenient size for small herds. The floor should be made of con- 

 crete, at least 18 inches wide, sloping toward the vat so that the 

 dripping from the cattle will flow back into the vat through the open- 

 ing provided. The floor at the sides of the chute is raised about 2 

 inches in the form of a curb to keep the dip from running off. 



The chute leading to the vat should be not more than 30 inches 

 wide and 20 feet long and it is desirable to have the receiving pen 

 and retaining chute large enough to accommodate the animals to be 

 dipped. 



PASTURE ROTATION. 

 TIME REQUIRED TO KILL TICKS BY STARVATION. 



The time necessary for ticks to die out on a pasture after removal 

 of the cattle is of importance with reference not onl}' to methods of 

 eradication by rotation but to methods of eradication by dipping. 

 When systematic dipping is begun and further infection of the pasture 

 is stopped by killing all ticks that get on the cattle, the period during 

 which the dipping must be continued in order to secure eradication 

 is prmiarily dependent upon the length of life of the seed ticks 

 already on the pasture and of those that hatch out from eggs laid by 

 ticks that dropped before dipping was begun. 



The time required for the ticks to die out after all animals have 

 been removed from infested fields and pastures varies considerably, 

 depending principally on the climate and the weather. The dates 

 when pastures will be free of ticks after all cattle have been removed 

 are given in the following table : 





