88 MANUAL OF MILK PRODUCTS 



Influence of the stage of lactation on the color of the whey. 



When the results are arranged according to the stage of lacta- 

 tion of the cows, the differences here are not very pronounced, 

 and are hardly definite enough to warrant any conclusions. A 

 calculation, however, shows that 78.5 per cent of the cows which 

 had been in milk for less than five months gave a color reading 

 slightly below the average of the breed. 

 Influence of the age of the animal on the color of the milk whey. 



An examination of the data indicates that the age of the animal 

 may slightly influence the color of the whey. Nearly all the 

 cows over seven years of age, especially the Jerseys, gave color 

 readings above the average for their breed. Of the cows under 

 seven years of age, 70 per cent are below the average. This 

 would indicate that the older the cow, the higher the color of the 

 milk whey. Three of the old cows, however, were also well 

 advanced in lactation, which may cause the apparent influence 

 of the age to lose some of its significance. 

 Influence of the volume of milk production on the color of the milk 

 whey. 



If the average milk production and average color reading 

 of the Holstein cows are compared with the average milk 

 production and average whey color of the Jersey cows, the 

 highest color evidently accompanies the lowest milk pro- 

 duction. This does not hold good, however, when comparing 

 either the Jerseys or the Holsteins with the Ayrshires. Simi- 

 larly the relation of high color to low milk production does 

 not hold good when comparing the Jerseys or Holsteins among 

 themselves. 



It must be concluded, then, that the differences in color of the 

 whey among different cows, while perhaps influenced in some 

 cases by the volume of the milk, is not primarily a dilution effect. 

 If any interpretation at all can be put upon the figures given 

 in the tables, it seems that the variation in the color is primarily 

 a breed characteristic, as stated before, with the milk yield, age 



