Studies in Mii.k Secrktion. 8i 



sumed the larger amount of food. Five records of old cows are 

 given. In milk production these vary from 518 to 654 pounds, 

 and these same two records vary in dry matter consumed from 312 

 to 250 pounds respectively. Here again, as among the three - 

 year olds, the larger yield of milk is accompanied with the smaller 

 consumption of food. It should be added that these two records 

 were made by the same cow, Helena Burke, one at five years of 

 age and the other at seven. She shows a better capacity for the 

 economic use of food at seven than at five. Indeed, she and No. 

 loi, America 2d's Pauline DeKol among three-year olds are 

 remarkable animals in this respect as well as in the large records 

 they have made for milk and butter. 



lender E we have a vivid comparison of the largest and smallest 

 amounts of food required to produce 100 pounds of milk in 

 different animals. Among the two-year olds No. 57 required 141 

 pounds of dry matter to produce 100 pounds of milk, which is 

 the most required by any cow of any age. It may be said in her 

 favor that she was not in good condition. She was so hard a 

 milker that it was necessary to use the knife to enlarge the 

 orifices of the teats which w^ere not healed at the time of test, 

 thus rendering the milking operation very uncomfortable to her 

 and doubtless reducing the quantity. The two-j^ear old requir- 

 ing the smallest amount of dry matter for 100 pounds of milk is 

 No. 60 The difference between the largest and smallest amounts 

 is 81 pounds or 135 per cent. In like manner, we find that the 

 difference between the largest and smallest amounts required by 

 three-3^ear olds is 60 pounds or 180 per cent, by four-year olds 

 about 46 pounds or 94 per cent, and by full aged cows nearly 52 

 pounds or 136 per cent. 



Under F are shown the largest and smallest amounts of food 

 required to produce one pound of fat in different animals at va- 

 rious ages. For two-3'ear olds the difference between these 

 amounts is about 28 pounds of dry matter or 160 per cent, for 

 three-year olds 21.5 pounds or 136 per cent, for four-year olds 

 10 pounds or 63 per cent, and for full aged cows over 18 pounds 

 or 154 per cent. 



Summing up the observations under E and F, we find the order 

 of the per cent of variation from the largest to the smallest 



