AGRICULTURAL EXPERIMENT STATION. 41 



has been: Holstein 25.22 cents, Ayrshire 26.82 cents, Jersey 

 20.43 cents, or in the ratio of 100: 107: 81. 



A pound of milk solids has been produced by these six cows 

 at an average food cost of 7.3 cents, which bears to the cost 

 of a similar amount of edible material in a steer's carcass an 

 estimated ratio of 100: 350. 



(6.) The average composition of the milk for two years has 

 been: Solids in 100 lbs.. Holstein, 12.22 lbs.; Ayrshire, 12.98 

 lbs.; Jersey, 15.24 lbs., or in the ratio of 100: 108: 125. The 

 pounds of fat in 100 pounds of milk have been: Holstein, 3.47 

 lbs.; Ayrshire, 3.67 lbs.; Jersey, 5.50 lbs., or in the ratio of 

 100: 106: 158. In general the milk has grown richer in solids 

 (and fat) up to the time of "drying off." 



(7.) The ratio of the quantity of nitrogenous compounds 

 (mostly casein) to the butter fat has been subject to consider- 

 able variation but does not seem to have been controlled by 

 changes in the food or season, or to have been modified by 

 an advance in the period of lactation. The proportion of 

 milk solids is affected by breed, however. The casein (and 

 albumen) being represented by 100, its ratio to the butter fat 

 is seen to average: Holstein, 100: 111, Ayrshire, 100: 108; Jer- 

 sey, 100: 134. 



(8.) The average percentages of total solids and of fat 

 in the skimmed milk for the two years give: Solids, Holsteins, 

 9.50 per cent.; Ayrshire, 10.40 per cent.; Jersey, 10.50 per 

 cent. Fat, Holstein, .52 per cent.: Ayrshire, .85 per cent, and 

 Jersey, .37 per cent. In general the skimmed milk has grown 

 richer in total solids and in fat as the time of parturition 

 approached. The average composition of the butter milk 

 has been: Solids, Holstein, 9.70 per cent; Ayrshire, 10.00 per 

 cent.; Jersey, 10.30 per cent.; Fat, Holstein, .45 per cent.; 

 Ayrshire. .44 per cent.; Jersey, .19 per cent. The composi- 

 tion of the skimmed milk and butter milk has not been greatly 

 different. 



(9.) The percentage of butter fat in the cream has aver- 

 aged: Holstein, 18.30 per cent.; Ayrshire, 17.00 per cent. 

 Jersey, 19.80 per cent. As the time of parturition has 

 approached the amount of fat has been less in proportion to 

 the other solids in the cream, than while the cows were 

 "fresh." 



2D 



