vi i] BACTERIA IN BUTTER-MAKING 129 



Influence of Lactation, Breed, Age, and Food 



on Quality of Butter. Among the other conditions 

 which influence the quality of butter may be 

 mentioned the lactation period, the breed, and the age 

 of the cow. Butter made from the milk of cows 

 which have been milked for some time is generally 

 firmer than that made from the milk of newly milked 

 cows, and possesses a less fine flavour. With regard 

 to the influence of feeding on the condition of the 

 butter, it has been proved that both the colour, the 

 flavour, the smell, the keeping qualities, and, in a 

 very special degree, the solidity of the butter-fat, are 

 dependent on the nature of the food used. Especi- 

 ally intimate seems to be the relation between the 

 food and the fatty acids. The volatile fatty acids 

 are at their maximum with a new period of lactation 

 and at the beginning of the pasturage season, and 

 decrease with the advance of the season and period 

 of lactation. There seems to be no connection 

 between the fat in the food and the fat in the 

 butter. From extensive experiments carried out 

 on the effect of food on butter, Professor 

 Adolf Mayer has come to the conclusion that 

 rations rich in carbohydrates have a favourable 

 effect in increasing the volatile fatty acids. It 

 must be frankly admitted, however, that the evidence 

 on the effect of different foods on the composition of 

 butter is very conflicting. Some interesting experi- 



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