l60 SCIENCE AND PRACTICE OP CHEESE-MAKING 



to the eighth months. Cows kept under ordinary 

 farm conditions are subject to greater variations 

 of external influences than those used in the investi- 

 gation represented by the figures in the preceding 

 table. The figures in the table on page 159 repre- 

 sent results secured in New York and Wisconsin. 



Influence of change from barn to pasture upon 

 the percentage of fat in milk. — In the course of a 

 study of cheese-factory milk in New York, it was 

 noticed that, under certain conditions, a marked 

 change in percentage of fat in milk took place. 

 Each year while the study of factory- milk was carried 

 on, it was observed that about the middle of May. 

 there was a considerable increase in the percentage 

 of milk-fat, accompanied by an increase of other 

 solids and also by a larger yield of milk. Thus, 

 during the first half of May, the milk contained 

 3.46 per cent of fat and, during the second half, 

 3.70 per cent. These results are in agreement with 

 those reported by the Vermont and Wisconsin ex- 

 periment stations and also by the Ontario agricul- 

 tural college. This question has been more thor- 

 oughly studied at the Vermont experiment station 

 than elsewhere and, according to the results ob- 

 tained during a series of years, the general rule 

 shows a change like that noticed above, but in some 

 years little or no change could be observed. A 

 careful study of all the available facts appears to 

 justify the explanation that the increased per- 

 centage of fat in milk under the given circum- 

 stances was due to a marked change In the char- 

 acter of the food and environment of the cows, 

 since they were turned out to pasture about the 



