168 TYPES AND MARKET CLASSES OF LIVE STOCK 



investigation. They were registered Jerseys, sired by the same 

 bull, from dams distantly related, and they had been raised 

 under practically the same conditions. The following table 

 gives the facts regarding these two cows during the first two 

 milking periods prior to the investigation: 



Name Pedro's Ramaposa Pedro's Elf 



Date of birth Sept. 4, 1902 May 11, 1903 



Age at first calving 29 mo. 18 mo. 



Pounds milk, first lactation period 4552 878 



Pounds fat, first lactation period 238 . 8 44 . 1 



Number of days in milk 337 131 



Pounds milk, second lactation period .... 7174 3189 



Pounds fat, second lactation period 377 114 . 8 



Number of days in milk 365 232 



During these two lactation periods, Pedro's Ramaposa 

 produced 2.8 pounds of milk and 3.9 pounds of fat for each 

 pound produced by Pedro's Elf. While the second milking 

 period was in progress, an investigation was planned to deter- 

 mine the cause of this difference in efficiency as dairy cows. 

 The cows were therefore bred so that the calves might be born 

 as near the same time as possible; Pedro's Elf calved October 

 4, 1907, and Pedro's Ramaposa calved October 7. 



Complete records were kept of the amount and compo- 

 sition of the feeds consumed. Each cow was fed a ration of 

 the same composition at all times, but the amount was varied 

 to suit the individual. As there was a possibility of the inferior 

 cow using part of her feed for depositing fat on her body a 

 characteristic of inferior dairy cows each cow was fed such 

 an amount as would keep her at a uniform body weight. Thus 

 the feed consumed could be studied in relation to dairy qualities 

 only. They were fed all they would consume, unless they began 

 to lay on flesh and gain in weight. The refused feed was col- 

 lected, analyzed, and deducted from the records. Complete 

 records were kept of the milk produced and of its composition. 

 The same man always milked both cows. In order to eliminate 

 another disturbing factor from such an experiment, the cows 

 were kept farrow; had they carried calves, it would have been 

 impossible to have accurately measured the feed requirements 

 for milk production. A digestion trial was conducted when the 

 cows were at their maximum production to ascertain whether 

 any difference existed in the efficiency of digestion. 



At the end of the milking period the cows were kept far- 

 row and the same ration was fed as during the milking period; 

 this was continued for 90 days, the feeding being so regulated 



