534 



Bulletin 169. 



In this comparison there are 97 records of milk and 93 of fat 

 production, 25 of the milk and 21 of the fat records being of two- 

 year olds. Of the remainder the same number of animals are 

 represented in both milk and fat, and of these, 25 are three year- 

 olds, 18 four-year olds and 29 full aged cows. The average yield 

 of all the cows was 6926 pounds of milk and 255.85 pounds of fat 

 with an average of 3.67 per cent fat. The average increase in 

 milk was five per cent from two to three year olds, 18 per cent 

 from three to four year olds, and 15.3 per cent from four- 

 year olds to full aged cows. The average increase in production 

 of fat was 5.5 per cent from two and three year olds, 17 per cent 

 from three to four year olds, and 13.6 per cent from four-year 

 olds to full aged cows. 



It will be noticed that the greatest increase in both milk and 

 fat is from the ages of three to four while the smallest increase 

 is from the ages of two to three. This is quite contrary to what 

 was found in the case of seven day tests of thorough bred Hol- 

 stein-Friesian cows, the records of which were published in Bul- 

 letin No. 152 of this Station. The gains of the older cows over 

 the younger were so different in the two cases that the per cent 

 increase in each is given in tabular form below for ready com- 

 parison. 



PER CENT INCREASE. 



Were it a question as to which gives the more accurate esti- 

 mate of the producing power of older cows over younger, the 

 choice would undoubtedly fall to the records here given of the 

 University herd. The latter is kept under conditions such as 



