96 Bulletin 152. 



the middle of the day, whi e of the 57 instances of lowest 

 daily per cent, 33, or over one-half, came at the morning milking. 



In considering those cows which w^ere milked four times daily, 

 it will be practically correct to count the four and six o'clock 

 milkings together, and the other milkings in the same order as 

 arranged in the table. Then for the complete summary we 

 have 98 instances where the milk reached its highest daily per 

 cent of fat, of which 46, or nearly one-half, occur at the noon 

 hour, and twice as many as at any other time. In the lowest per 

 cents of fat there is ver}^ little difference between the number of 

 instances at morning and afternoon milkings. 



These figures then, bear cut the statement made above, that 

 the milk drawn at noon has a tendency to average higher in per 

 cent of fat than the milk drawn at other times during the day, 

 and this seems to be true whether the milking be at equal 

 or unequal intervals. The lo^ st per cents of fat, however, do 

 not so invariably occur at ne morning milkings as when 

 the cows are milked at unequa intervals with the longest period 

 invariabh^ between night and morning. When the milkings are 

 at equal intervals the honors are divided between morning and 

 night, especially if there be four milkings daily. It would be of 

 interest to know the causes of all these variations, but at present 

 we are more or less in the dark in regard to them. Ma}^ it not 

 be that the higher per cent of fat at noon is partly the result of 

 the warmer and more even temperature surrounding the animal ? 



x\s to the range of variation in the per cent of fat during the 

 week found in different animals, the following summary from 

 Table III will give some indication. 



Age. Greatest Variation. Least Variation. Average Variation 



Two-year olds 3.60 40 1.42 



Three-year olds 3. 20 60 .... i .48 



Four-year olds 3.00 75 1.76 



Full-aged cows 4.10 70 1.76 



Average of all cows 1.60 



The greatest average variation is found among those animals 

 w^hich we would naturall}^ suppose to be most constant in their 

 per cent of fat, namely, the older cows. The average variation 

 for four-year olds and full-aged cows is exactly the same. The 



