CLEANING AND THE PROCUREMENT OF MILK 57 



into contact ; compared with these, contamination from the air 

 usually plays quite a minor part. 



An important influence on the quality of the milk is often 

 ascribed to the feeding, and it is well known that certain fat- 

 soluble colouring and odiferous matters contained in the fodder 

 may pass into the milk, and also that the composition of the milk 

 fat is largely influenced by the nature of the feed. At times the 

 natural acidity and the sensitiveness to the action of rennet may 

 be slightly influenced, but otherwise the chemical composition of 

 the milk is not sensibly affected by the factor in question 1 . It 

 should, however, not be forgotten that the feeding is the most 

 important factor in determining the consistency of the dung, and 

 the thinner the dung the dirtier the cows. Moreover, the feed 

 will directly or indirectly 

 determine the nature of the 

 bacteria predominating in 

 the dung, and thus the 

 nature and number of the 

 bacteria in the milk. . It will 

 therefore be understood that 

 the most important effect of 

 the feed on the quality of 

 the milk is of a bacterio- 

 logical nature, and this can 

 partly be eliminated by keep- 

 ing, the cows clean ; it is, 

 however, difficult to do this 

 properly if they are suffering 

 from diarrhoea, and it is 

 therefore of prime import- 

 ance to avoid all risk of digestive trouble. Sudden changes 

 in the feeding are especially to be avoided ; in spring, the first 

 green fodder should be given in the stable, gradually decreasing 

 the proportion of dry fodder. If diarrhoea occurs in winter, the 

 proportion of beet must be decreased and the ration made up with 

 hay, while care must also be taken that the drinking water is not 

 too cold. Should the weather be cold and rainy in summer, the 

 cows should be kept in the shed at night, or supplied with covers. 

 Beet and turnip tops very often cause trouble, though this is rather 

 of a bacteriological than of a chemical nature. If the tops are not 

 given in large amounts, they will do no harm provided that they 

 have been harvested properly, but if they have lain in the field 

 and become wet and soiled with earth, they will develop undesir- 





FIG. 52. Rotting Swede containing numerous 

 Pectin- fermenting Plectridia. 



Orla-Jensen, " Landwirtschaftliches Jahrbuch der Schweiz," 1905. 



