No. G. DEPARTMENT OF AGllICULTUKE. 381 



in the body for the production of milk, meat, wool, etc., and it is 

 difficult to conceive how it can be of any value in the production of 

 muscular energy. 



3. All solid food requires some force to grind it and although this 

 force is changed into heat, yet whatever part of the food is used to 

 produce this force, certainly cannot be used to produce any work for 

 the owner, or to produce anything else of value. 



The particular part of the food that requires most of the energy in 

 grinding is the fibre. In general it can be said that the more fibre 

 a material contains the larger amount of energy will be required 

 to masticate it. An average figure is about 12()() units of energy 

 for the mastication and digestion of each pound of crude fiber in 

 the original food. As this crude fiber is on the average about half 

 digested, it will yield to the body about 700 units of energy. There- 

 fore when an animal from whom production is required is fed mate- 

 rial containing crude fiber, the animal gets 700 units out of each 

 pound and uses up 1200 in masticating it, or in other w'ord® each 

 pound of fiber in the food causes a net loss of about 500 units of food 

 value. This is about the amount of net value that is supplied by a 

 third of a pound of first class digestible food. In other words each 

 pound of fiber requires the value of a third of a pound more to 

 handle it. 



Nevertheless, fiber cannot be omitted from the food of our animals 

 for two reasons. The first is, that the system of the steer needs some 

 bulky material to distend the paunch and enable the animal to chew 

 the cud; the second reason is, that fibrous fodders are so much 

 cheaper than the non-fibrous that it is the part of commercial wisdom 

 to make use of these fodders even though they are not highly nutri- 

 tious. 



4. The three wastes so far enumerated are well known, and can 

 be estimated with a fair degree of accuracy. In addition to these 

 there is the amount of energy required to digest the food and the 

 amount used up by the body in carrying on the processes of life, of 

 respiration, circulation, etc. Experiments on the first of these are 

 not numerous, and have been fjerformed on non-ruminants. A rough 

 estimate can be made that after subtracting the energy required for 

 handling the fiber in the food', the energy for digesting the remainder 

 will be equal to ten per cent, of the value of the digested food other 

 than fiber. Experiments have not progressed far enough yet to 

 make any definite statement as to the amount of energy used in car- 

 rying on the processes of life. 



The kind of food probably has but little infiuence on the last 

 factors mentioned and as they will be fairly uniform for animals 

 under the same conditions, even though the food is varied, they can 

 be omitted in discussing the relative value of foods. 



