140 THE CHEMISTRY OF CATTLE FEEDING 



there will be [0-0218 X 35 =] 076 Ib. to 35 kt.,i.e. in 19 Ibs. 

 of hay. As 19 Ibs. of hay yields a sufficient amount of avail- 

 able energy, and contains rather more than the minimum 

 amount of protein required, it should form an adequate ration 

 for the maintenance of oxen of the size assumed. 



It will be seen on reference to the tables (p. 166) that the 

 T.F.V. of roots and succulent fodders, owing to the large 

 amount of water they contain, is much less than that of drier 

 materials. In most of the latter, it ranges from about 3! to 

 4 kt. per Ib., but in those which contain much oil it is higher. 



The thermic values of the foods do not exhibit the same 

 degree of uniformity, chiefly because of the difference in the 

 digestibility of the constituents, especially the cellulose. For 

 example, the T.F.V. of sawdust is about 4 kt. per Ib., but of 

 this total only about o'6 kt. is available. 1 In cakes, cereal 

 grains, and other concentrated foods of which the coefficients 

 of digestibility are high, the thermic value is from 70 to 80 

 per cent, of the T.F.V. Rape cake and undecorticated cotton 

 cake are conspicuous exceptions to this rule. Even in offals, 

 e.g. sharps, bran, brewer's grains, etc., the thermic values are 

 from 60 to 70 per cent of the T.F.V. In hays, straws, and 

 coarse fodders generally, the thermic value is generally less 

 than half the T.F.V. 



Cakes and grains are not much used for maintenance 

 rations. They are at once too concentrated and too expensive. 

 Ruminants, and also horses, require a certain amount of the 

 coarser fodders hay, straw, etc. and, in proportion to the 

 amount of thermic energy which the animals derive from them, 

 these foods are much cheaper than cakes and grains. 



The cost of various foods per 1000 kilo-pound-units of 

 static or thermic energy is given in the eleventh column of 

 the tables. Compared on this basis it appears that the roots 

 are the cheapest at the prices assumed. They cost from 

 about I4J-. to i6s. per 1000 kt. Sugar beet appear to be 

 even cheaper, but perhaps the price assumed is too low. A 



1 Owing to its effect on the digestibility of other foods when sawdust 

 is mixed with them, the actual value of the latter is less than o. 



