Studies in Milk Secretion. 63 



A close stud}' of Table I and its summary reveals a large varia- 

 tion in production between animals of the same age. Among 

 two-year olds the largest milk record for seven days is that of No. 

 62 (Lotty Moselle's Pietertje Mechthilde) with 362.5 pounds, 

 containing 9.764 pounds of fat and an average fat content of 2.69 

 per cent. The lowest milk record is that of No. 57 with 156.5 

 pounds, containing 5.301 pounds of fat and an average fat con- 

 tent of 3.39 per cent. The largest production of fat is that of 

 No. 31 (Pietertje Heno^erveld's Lady De Kol) with 12.675 pounds 

 from 300.375 pounds of milk containing an average of 4.22 per 

 cent fat, which is the highest average found among the two-year 

 olds The smallest production of fat is that of No. 5 with 5.263 

 pounds from 220.688 pounds of milk containing an average of 

 2.29 per cent fat, which is the low^est average found among 

 two-year olds. 



The average production for all two-j^ear olds is 279.537 pounds 

 of milk, 3. II per cent fat and 8.697 pounds of fat. 



Of the three-year olds No. loi (America 2d's Pauline DeKol) 

 leads in the production of milk with 520. 188 pounds, containing 

 15.903 pounds of fat and an average of 3.06 per cent fat. The 

 largest production of fat is by No. 76 (Mutual Friend 3d) with 

 17.472 pounds from 409.188 pounds of milk containing an aver- 

 age of 4.27 per cent fat which is the highest average found 

 among four-year olds. No. 95 produced the smallest amount of 

 both milk and fat, her record at this time being 228,625 pounds 

 of milk and 7.665 pounds of fat. The lowest per cent of fat was 

 given by No. 96 whose average was 2.56 ; her total milk and fat 

 3deld was 316.375 and 8.091 pounds respectively. 



The average production for all three-year olds was 359.234 

 pounds of milk, 3.22 per cent of fat and 11.555 pounds of fat. 



Among the four-year olds the one producing the most milk in 

 seven days is No. 125 (Debora's Inka) with 521.25 pounds con- 

 taining 15.188 pounds of fat and 2.91 per cent fat. The same 

 heifer (Mutual Friend 3d) that led the three-year olds as No. 76 

 in total yield of fat and in average per cent fat, also leads, as No. 

 121, the four-year olds in the same respect. Her yield of fat was 

 18.265 pounds from 427.938 pounds of milk containing an aver- 

 age of 4.27 per cent fat, or exactly the same percentage her milk 



