LABOR EEQUIREMENTS AND MILKING MACHINES. 13 



larger herds when the milking machine is used. Each of these items 

 will be considered in detail. 



INTEREST ON INVESTMENT. 



Interest on investment is a widely variable item. When the type 

 of milker used is the same, the investment charge per cow is much 

 smaller in the large than the small dairies. This is because a power 

 plant, piping, etc., have to be installed in the small as well as in the 

 large dairy, and the difference in the costs of these equipments is 

 not proportional to the number of cows they serve. There is con- 

 siderable variation in the costs of the different kinds of mechanical 

 milking outfits on the market. The comparatively expensive outfits 

 are more frequently used on the farms having larger dairies ; there- 

 fore, the investment per cow is not as much smaller in these large 

 herds as it would appear that it should be. 



COST OF POWEE. 



The cost of power per cow falls slightly as the number of cows 

 milked increases. The time consumed per cow is greater in a small 

 herd than in a large one. 



Power for the operation of milking machines is usually furnished 

 by means of a gasoline engine. It does not ordinarily pay to use an 

 engine which develops much excess power, as it requires too much 

 gasoline. '\Miere it is necessary to pump water this is often done 

 at milking time, and a larger engine may be profitably used to do 

 the extra work. The cost of power furnished by a gasoline engine 

 depends on the local prices of gasoline and oil, and the efficiency 

 with which the engine is operated. Electric motors are sometimes 

 used as a source of power on farms near large towns where current 

 from a power line is available. This form of power is sometimes 

 more expensive, but perhaps is more reliable than gasoline. In 

 special cases, as, for example, where the herd is large and extra labor 

 for emergency hand milking not available, it may sometimes be worth 

 the extra investment incurred to have a second gas engine large 

 enough to operate the milker, set up in such a manner that in case 

 of accident to tlie engine regularly used it could be pressed into 

 service without loss of time. 



REPAIRS. 



The repair costs seem to he greater per cow for the larger herds. 

 This is probably due to the fact that with such herds more cows are 

 milked with a milking unit than with the smaller herds. The repair 

 costs are largely confined to the rubber tubing and rubber linings of 

 the teat cups. 



