CATTLE LICE AND HOW TO ERADICATE THEM. 23 



that the animals can not brace themselves on it for a leap as easily 

 as on the long, gradual slide. > 



The exit incline or crawling board in small vats should be about 

 16 feet long, so that the incline may not be too steep. In cement 

 vats a false floor to which the cross cleats are nailed is usually laid 

 on the exit incline. Bolts should be embedded in the concrete for 

 fastening the false floor. The plans for the concrete vat show the 

 lower end of the floor held in position by a cross pipe embedded in 

 the concrete and the upper end and middle held by bolts. 



If permanent pipes are used for conducting water and dip to the 

 vat they should be laid so as not to act as obstacles to the men work- 

 ing along the vat. There should be no obstruction in the path along 

 both sides of the vat; neither should there be any cross pieces over 

 the top of the vat that may interfere with the proper handling of 

 the cattle while they are in the dip. 



The wooden vat shown in the plans has sloping sides, but, as 

 already stated, they may be made perpendicular if desired. When 

 soft wood is used for the frame timbers they should be 6 by 6 inches, 

 but if hard wood is used 4 by 4 inch timbers are sufficiently large 

 for the purpose. Cedar posts make good framing timbers, as they 

 do not rot rapidly. Matched planks 2 inches thick should be used 

 in building the vat, and they should be beveled so that all joints and 

 seams may be properly caulked with oakum and rosin or similar 

 material. 



A water trap with hinged cover is shown in the exit incline of 

 the wooden vat. While dipping is in progress both the cover and the 

 valve to the drain pipe should be closed, but when dipping is finished 

 for the day both should be opened so that water from the draining 

 pens in case of rain may not run into the vat and dilute the dip. 



Heating equipment is necessary in the case of those dips which 

 are used warm. That shown in the plans of the wooden vat may 

 also be built in connection with a cement vat. When the open-tank 

 heating system shown in the plans is used settling wells are not neces- 

 sary, as the heating tank answers the purpose of a settling well. 

 This system has an advantage over the old-style coil heater in that 

 the pipes may easily be kept from clogging. Another method of 

 heating, and the one usually employed, is to install a 25-horsepower 

 boiler and to pipe the steam to the vat, where it discharges into the 

 dip through perforations in a pipe laid along the bottom of the vat 

 for about two-thirds its length. The water condensing from the 

 steam passing into the vat from the boiler dilutes the dip to a slight 

 extent, and for this dilution an allowance should be made in re- 

 plenishing the dip. 



The trench for the vat should be excavated so that the inside 

 dimensions correspond with the outside dimensions of the com- 



