FIRST CENTURY OF DAIRYING IN NEW SOUTH WALES. 



Scientists tell us that heat is produced in the silage owing to the 

 rapid union of the oxygen of the air with the combustible atom- of 

 the -fodder in the stack, pit, or room, consequently the object of ad- 

 mitting or excluding by controlled pressure or closeness in packing, 

 the air from the confined fodder is to regulate the temperature of 

 the mass at will, so as to produce either sweet or sour silage or 

 ensilage in a partly assimilated form. 



When the carbo-hydrates, so called because they contain, in ad- 

 dition to carbon, hydrogen and oxygen in proportion to form water. 

 and the cellulose whicn forms the solid substance of most plants 

 in their green state, and which is not soluble in water, but dis- 

 solves in a weak acid), gets overheated and burns in the stack, or 

 pit, or room, the hydrogen and oxygen being in proportion, in the 

 one, to form water, cleates a volatile vapour; while the carbon com- 

 bines with oxygen from the air forming rarbonic dioxide, com- 

 monly called carbonic acid. The farmer has, therefroe, to guard 

 against overheating and the formation of too much acid. As it is 

 impossible to exclude all the air from the silage mass, thersj must 

 be continual combustion going on within the mass from month to 

 month until in time the whole mass would be consumed. " Now. 

 according to this theory, silage would not keep for any length of 

 time, whereas instances are frequent where silage has been kept in 

 a wholesome state 'for a number of years, which goes to shew that 

 once the generation of carbonic acid is arrested in the mass it may 

 remain in the same condition for many years. 



As the heating and chemical changes in the fodder are mainly due 

 to the oxidising action of the living substances of the cells of which 

 the plants making up the fodder are composed, it was thought, if 

 pressure was put on the mass immediately, this living substance re- 

 quires to take its oxygen out of the other cell contents, the air being 

 shut out as a source of supply, the desired condition of the silage 

 could easily be controlled. We have had many disappointments, 

 however, where much success was looked for, and many successful 

 experiments have been carried out under the most careless conditions 



These object lessons, however, do not disprove the theory so 

 often expounded, namely, that when the heat increases very gradually 

 and the matter of the fodder goes through the various stage - < ;" 

 starch, sugar, alcohol, and acetic acid, no. matter whether the mass 

 be in a pit, stack, or room, good results invariably follow. Rut it 

 must be remembered that it is the acid which gives the sour taste 

 to silage, which stock soon begin to relish; it also conveys a peculiar 

 taint to milk. There is one advantage to be gained by making sour 

 silage ; that is, it will keep for a longer period of time in a whole- 

 some state after being cut out of the mass than any other form < f 

 silage, which is important. In this case the temperature of tr.e 

 -ilage should not be allowed to go above T2odeg. Fahr. 



On the ntlu-r hand. SWCCl silage is made by putting on the pressure 

 for a short time so as to allow the temperature to rise to i-jodeg. 

 Fahr. Once above i3Odeg. Fahr., the heat kills the cells when they 

 by chemical change have formed sugar, and before they ha\e time 

 to form acetic acid. If the heat is allowed to rise above I5odeg. 

 Fahr.. the silage becomes burnt and disagreeable. We therefore 

 should expect to see the best silage made at a temperature of ijp'lcg 

 Fahr.. which is theoretically the happy medium between sour and 

 -weet ^ilagc. The figures would then range as -follows: T2odeo:.. 

 sour silage ; i^odrg.. ^lightly acid ^ilage ; I5odeg., sweet silage. The 

 color of the -our silage should be an orange green, and the sweet 

 -ilage should be a dark brown color. 



I'nt the-e rules cannot be depended on at all times ; they ar" 

 merely a .uu!<!e <n ,\\l:cl\ to \\crk in rder to arrive at the best 



312. 



