192 Types and Market Classes of Live Stock 



gan to lay on flesh and gain in weight. The refused feed was collected, 

 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 con- 

 ducted 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 farrow and 

 the same ration was fed as during the milking period ; this was continued 

 for 90 days, the feeding being so regulated in quantity as to maintain 

 the cows at a uniform body weight. In this way the requirement for 

 maintenance was determined for each cow. A maintenance ration is 

 one that will maintain a resting animal at a uniform body weight; 

 such a ration keeps up the body heat, makes repairs in the tissues, and 

 furnishes energy for the working of the heart, lungs, digestive and 

 other organs, and for slight movements of the body. If the dairy cow 

 is pregnant, she requires enough feed above maintenance to furnish 

 nourishment for the foetus. Still more feed in excess of maintenance 

 is necessary if she is giving milk as well as carrying a calf. Cows vary 

 somewhat in their maintenance requirements, hence two cows con- 

 suming the same amounts of feed may have different proportions of 

 their feed available for milk production. For instance, a restless cow 

 has a greater maintenance requirement than a quiet one; when standing 

 up, more feed is required for maintenance than when lying down. 

 Many other factors affect the requirement for maintenance. It is 

 therefore apparent that an investigation into the cause of difference s 

 in the economy of production is not complete unless the requirement 

 for maintenance is determined. This the Missouri Station did by 

 finding how much feed was necessary to maintain each cow at a con- 

 stant body weight while dry and farrow. Other experiments have 

 shown that a well-fed dairy cow uses about 43 per cent of her feed for 

 maintenance, 30 per cent in the work of converting feed into milk, and 

 about 20 per cent finally appears as milk. These percentages vary, 

 depending on the nature of the feed and the individual, but a good dairy 

 cow is more efficient as a machine than either the horse or the steam 

 engine. In the Missouri experiment it was found that the higher-pro- 

 ducing cow required slightly more feed for maintenance; hence, the 

 wide variation in production could not be accounted for by a superiority 

 of the high-producing cow in regard to maintenance. 



During the year of the investigation, Pedro's Ramaposa produced 

 8,522 pounds of milk and 469.9 pounds of fat. Pedro's Elf produced 



