DAIRY CATTLE 



481 



have gained entrance to the milk. More- 

 over, the thickness of the cream, when 

 the separator is used, may be regulated 

 at will, whereas by the gravity system 

 the amount of fat is never higher than 

 20 per cent. The fat is more completely 

 removed by the use of a separator than 

 by any gravity system and the skim milk 

 is obtained sweet and in the best possible 

 condition for feeding to calves and other 

 animals. 



Separators — The idea of separating 

 cream by centrifugal force was appar- 

 ently first suggested in 1859, but the 

 apparatus devised for this purpose was 

 somewhat clumsy and unsatisfactory un- 

 til 1879, when the Weston and De Laval 

 separators were invented. The essential 

 feature of all separators is the bowi 

 which revolves in a vertical position, 

 and may or may not be furnished with 

 various devices on the inside. The milk 

 may be allowed to enter the top or bot- 

 tom of the bowl, but in most machines 

 it enters at the top. It is at once acted 

 upon by the centrifugal force in the re- 

 volving bowl and separates into three 

 layers, a thick layer, commonly known 

 as the separator slime, next to the outer 

 wall; the skim milk layer coming next, 

 toward the center and the cream in the 

 center; the richest cream being in the 

 center of the bowl. The rate of feed 

 may be regulated by a simple device, 

 and directions for all the practical de- 

 tails of operating separators are fur- 

 nished with each machine. It is best to 

 follow these directions closely, for the 

 reason that they have been thoroughly 

 tested by the manufacturers and others, 

 and the recommendations are based on 

 the results of these experiments. The 

 rate of revolutions varies from 6,000 to 

 9,000 or more per minute in different 

 machines and the manufacturers of each 

 machine indicate the rate at which the 

 best results are to be obtained. This 

 recommendation must also be followed. 

 The machine should be started slowly 

 and the proper speed obtained by grad- 

 ually increasing the rate of revolution. 

 The milk should not be allowed to enter 

 until the right speed has been attained. 

 A considerable number of separators 

 are ^advertised for use on the farm. 

 These include the De Laval, the United 

 States, Sharpies, Iowa, Simplex, Omega, 

 Empire, Davis, National, Dairy Queen, 

 Westphalia, Peerless and Skimclose. 



Naturally a keen rivalry exists among 

 the manufacturers of these different 



machines in claiming superior advan- 

 tages for each machine. It would be 

 quite useless to attempt in this connec- 

 tion to determine the relative value of 

 different makes of separators. They dif- 

 fer not only in strength, closeness of 

 skimming, simplicity, and height of 

 the receiving can, but also in the rate of 

 speed required, durability, capacity, 

 power required for turning and other 

 points. The low position of the receiv- 

 ing can is claimed by some makers as a 

 great advantage, but it is obvious that 

 this advantage is of little importance 

 if it is obtained by sacrificing the mech- 

 anical strength and durability of the 

 machine. The amount of cream left in 

 the skim milk by separators ranges from 

 .1 to .2 per cent. 



Separating milk — Milk may be run 

 through the separator fresh from the 

 cows, or, if allowed to become cool, 

 should be heated before separation. In 

 general, the higher the temperature the 

 more fluid the milk and the easier the 

 fat is removed. When milk is heated 

 after becoming cool the temperature 

 should be raised gradually. If the milk 

 has partially soured or the cream has 

 partly risen so as to form stringy masses, 

 these conditions may interfere some- 

 what with the effective operation of the 

 separator. Care must also be exercised 

 not to overfeed the separator, or to 

 change the speed during the operation 

 of the machine. After a little experi- 

 ence, this matter is learned so that the 

 operator may maintain a uniform stroke 

 of the handle. 



According to McKay and Larsen, the 

 use of farm separators has increased 

 enormously within recent years. Thus, 

 hand separators were introduced into 

 Iowa in 1894; in 1898 there were 904 

 farm separators in the state, while in 

 1904 there were more than 17,000 and 

 the number has increased greatly since 

 that date. The reasons for this rapid 

 extension of the use of farm separators 

 have been well stated by McKay and 

 Larsen. In the first place, the farmer 

 obtains his skim milk in the best con- 

 dition for feeding. The cost and trouble 

 of hauling the milk to a creamery are 

 avoided. The use of farm separators 

 puts the farmer in a more independent 

 position. The chief objections to farm 

 separators are due to their careless use 

 by the average farmer. If the separa- 

 tors are not kept in an absolutely clean 



