326 



EFFECTS OF FOOD AND SEASON 



changes of food upon cows at pasture, upon the composition of their 

 milk. 



He found that the addition of a food rich in albuminoids (gluten 

 meal) produced an increase of 3*75 per cent in the quantity of milk, a 

 very slight increase, 0'03 per cent, in the proportion of fat and of 0'08 

 per cent in that of solids-not-fat ; that a food rich in carbohydrates 

 (maize meal) gave an increase of 2'95 per cent in the yield of milk, 

 but that the fat content of the milk was diminished by 0*18 per cent 

 and the solids-not-fat by 0*03 per cent. 



The improvement in the amount and quality of milk which usually 

 ensues when cows are turned out to pasture in the early spring is not 

 to be attributed entirely to the change of food, but largely to the more 

 healthy and natural character of the conditions of life and, perhaps 

 most of all, to the increased quantity of food which the animals then 

 consume. In England, the change in the milk when the cows are 

 turned out to grass is usually said to be an increase in quantity, but 

 with a lower fat content. Broadly speaking, it may be said that if the 

 cows are sufficiently fed, a change of food produces, at most, a tempor- 

 ary effect upon the quality of the milk. 



The flavour of milk and butter and especially the chemical char- 

 acter of the milk-fat are greatly affected by certain foods. Certain oil 

 cakes, if used in large quantities, have a marked effect upon the melt- 

 ing-point, iodine value, proportion of volatile acids and other char- 

 acteristics of the fat of milk. Foods with strong flavours often impart 

 their characteristics to milk. 



Influence of season. According to the numerous analyses of Rich- 

 mond and Vieth, 3 the winter's milk is richest, the summer's poorest, 

 while milk in spring and autumn is of intermediate quality. 



1 Total cost of food, less value of obtainable manure. 



2 Assuming butter to contain 82-4 per cent fat and 96-3 per cent of the total fat 

 of the milk to be obtained as butter. 



3 Dairy Chemistry, 127. 



