BULLETIN 159.1 [JUNE, 1907 



Ontario Department of Agriculture. 



ONTARIO AGRICULTURAL COLLEGE 



MILKING MACHINES. 



By H. H. Dean, Professor of Dairying. 



The milking- of cows by machinery is a very live topic at the present 

 time among dairymen. Having had considerable experience with these 

 machines, we may be allowed tq discuss the matter briefly. All our spare 

 time for experiments in the dairy stable during the past year has been 

 devoted to a study of the problems connected with the milking of cows 

 by machinery. We shall consider the question from three viewpoints, 

 viz., physiological, mechanical, and practical operation of the'machines. 

 We shall also give results of experiments made this year. 



Under physiological, we may first look at the various theories which 

 have been propounded in order to explain the secretion of milk. The 

 problem is a very complicated one, and no very satisfactory explanation 

 of milk secretion has yet been offered. One theory says it is the result # 

 of changes in the cells which go to make up the organ of the cow known 

 as the udder. fn other words, according to this theory, milk is the 

 liquefied cells which largely compose the mammary glands. The chief ob- 

 jection to the metamorphic or change theory is that a cow giving a large 

 quantity of milk would have to build up the cells of the udder several 

 times during a day, which is practically impossible for hei to do. 



The second theory is known as the transudation or filter theory, 

 which assumes that milk is merely filtered from the blood by the mam- 

 mary glands. The chief objection to the filter theory is that blood and 

 milk are not of the same composition. There are substances found in 

 the milk which are not found in the blood, e.g., casein, which is prob- 

 ably the result of cell action. If we combine the metamorphic and trans- 

 udation theories regarding- milk secretion we shall probably have the 

 most satisfactory explanation of the mysterious process of milk secre- 

 tion. 



There is also the ferment theory, which ascribes the secretion of 

 milk to the action of ferments in the cow's udder. We are not inclined 

 to favor this theory, although it may explain some of the nhenomena 

 in connection with milk secretion. 



There is nothing in the physiological processes so far as we can see, 

 to prevent the satisfactory milking of cows by machinery, and we have 

 always had faith that such a machine would become practicable. Nearly 

 all modern milking machines have been operated on the principle of suc- 

 tion, or have imitated the milking of cows by calf sucking. We have 



