MANUAL OF CATTLE-FEEDING. 369 



of the ration must be made up of bulky fodder, containing 

 nuicli indigestible matter and serving to make up the neces- 

 sary volume, while if this excess is small, a larger portion 

 of the ration must consist of easily digestible feeding-stuffs. 



In the feeding standard given above as an illustration, a 

 certain quantity of digestible fat is called for. It is at pres- 

 ent impossible to state with any certainty the most suitable 

 quantity of this substance, since so few experiments have 

 been.,made on the subject, and even these are by no means 

 accojd^jil;. We know that the fat of the food appears to be 

 more easily stored up in the body than that coming from the 

 splitting up of the albuminoids (page 191), and that fat 

 is a more concentrated heat-producer than the earbhy- 

 drates, while, in its relations to the g^in and consump- 

 tion of flesh, it can be replaced by the latter. It may, 

 therefore, be assumed that the fat of the fodder plays a 

 direct and important part in the production of milk, in 

 fattening, and in the feeding of working animals, especially 

 horses, and that accordingly where a rapid pi*oduction is 

 desired, the amount of fat in the ration is of some mo- 

 ment. We shall, therefore, include the digestible fat as 

 such in the feeding standards, but rather as an indication 

 of its probable importance than as a statement of the quan- 

 tity of it which must be contained in the ration. 



Llmitatious of Feeding Standards. — Feeding stand- 

 ards being simply the concise expression of the results of 

 experiment and observation, it is plain that their value 

 nmst depend on the extent and accuracy of the observa- 

 tions on which they are based. Some of those to be con- 

 sidered in the following chapters are the results of many 

 careful experiments, and are worthy of much confidence. 

 Others, again, are based on but few observations, and are 

 confessedly only tentative. 



