ON FEEDING EXPERIMENTS. 351 



To feed an excess of fodder materials, as roots and potatoes, 

 which contain a large proportion of non-nitrogenous sub- 

 stances, as starch, sugar, digestible cellular substance, etc, 

 means direct waste ; for they are ejected by the animal, and 

 do not materially benefit the manure heap. In case of an 

 excessive consumption of nitrogenous constituents, a part of 

 the expense is saved in an increased value of the manure, 

 yet scarcely enough to recommend that practice beyond mere 

 exceptional cases. The aim, therefore, of an economical 

 stock-feeding must be to compound our various fodder mate- 

 rials in such a manner that the largest quantity of each of 

 the three groups of fodder substances which the animal is 

 capable to assimilate, should be contained in its daily diet to 

 meet the purpose for which it is kept. 



To compound the fodder rations of our farm stock with 

 reference to the special wants of ea'ch class of them, is an 

 essential requirement for a satisfactory performance of their 

 functions ; to supply these wants in an economical way con- 

 trols the financial success of the industry. 



The problem is an intricate one ; years of careful experi- 

 menting were required to accumulate observations sufiicient 

 in number and in quality, to impart to the conclusion arrived 

 at the claim of being worthy of a serious consideration. 

 The first attempt to lay down rules for compounding the 

 fodder rations of all kinds of farm stock on rational scientific 

 principles, was made by Dr. Grouven, director of the Agri- 

 cultural Experiment Station at Salzmiinden, Germany, 1858- 

 1864. He began his work with a critical compilation of 

 feeding experiments made by competent parties, some ninety 

 in number, his own extensive experiments included. He 

 ascertained in each case the amount of each fodder substance 

 consumed per day during each experiment ; and calculated 

 subsequently, from their analyses, the character and the 

 amount of the daily fodder rations. 



By this operation he learned the exact amount of nitroo"- 

 enous, non-nitrogenous and mineral substances digested per 

 day, under definite circumstances, by each class of farm ani- 

 mals. The amount of fat which had been fed in the fodder 

 substances was separately recorded, on account of its excep- 

 tionally high feeding value, as a heat-producing material. 



