142 THE CHEMISTRY OF CATTLE FEEDING 



day ; and it is upon these data that the estimates are based. 

 For the common articles of commerce cakes, grain meals, 

 etc. the comparison is perhaps more reliable than in the case 

 of home-grown products such as hay and roots. The former 

 are more constant in composition and the actual prices at 

 which they are sold and bought are easily ascertained from the 

 market reports published in the agricultural and daily papers. 

 The prices of hay, straw, and sometimes even of roots can be 

 ascertained in a similar manner, but this probably does not 

 give a fair basis of comparison. The cost of production, or 

 " consuming value," of hay on the farm is usually much less 

 than that of the same product in the London or Manchester 

 market, and it is very difficult to decide exactly what prices 

 should be assigned to such products. Potatoes, for instance, 

 are quoted in the papers at gos. to IQOS. per ton, but the chats 

 which are given to the pigs should certainly be priced at a much 

 lower figure. 



Notwithstanding all this, however, the broad fact remains 

 that the most economical maintenance rations for ruminants and 

 horses are those which consist most largely of roots, hay, and 

 straw. These foods should therefore be used to the largest 

 extent that is compatible with the conditions as regards the 

 amounts of protein and thermic energy required for simple 

 maintenance of the animals. In later chapters it will be shown 

 that it is not economical, but the reverse, to use larger 

 quantities of the coarse fodders. 



These inferences are entirely consistent with the universal 

 practice, based on experience, of farmers, and the fact may 

 be regarded as strong confirmation of the truth of the theories 

 from which they are drawn. It was, of course, unnecessary 

 to prove what is accepted, but a knowledge of the theoretical 

 aspects of the subject gives the farmer a valuable means of control 

 in these and in more complex cases ; and further arguments 

 will be based on the conclusions thus shown to be sound. 



NOTE. If 9 Ibs. be the amount of total digestible nutrients required 

 by oxen of 1000 Ibs. live weight, the requirements of those of any other 

 size can be calculated directly by the formula : log N = 0*7 log M 1*145. 

 N is the amount (Ibs.) of digestible nutrients. 



