H. E. Woodman 145 



grow and utilise maize forage for ensilage, and consequently the attention 

 of agriculturists has been directed towards the discovering of other crops 

 which are suitable for being grown for silage. A large measure of success 

 has attended these efforts. Aniosi, for instance, has shown that a mixed 

 crop of oats and tares jjossesses all the characteristics for the successful 

 inclusion of the jDractice of ensilage in the ordinary farm routine. 



It would, therefore, be unsafe to assume that the results obtained in 

 American trials with maize forage apply with equal force to the methods 

 of ensilage which are being adopted in this country. Concurrently with 

 the extension of the practice, it is necessary to prosecute enquiries with 

 a view to obtaining satisfactory answers to such ci[uestions as those 

 enumerated above. Investigations are proceeding in all these directions 

 at Cambridge, and the work to be detailed in the present communication 

 was undertaken in order to obtain a direct comparison of the digestibility 

 of oat and tare silage not only with oat and tare hay, but also with the 

 green oats and tares from which both hay and silage had been produced. 

 Such information must be taken into account when coming to a decision 

 as to the relative merits of ensihng and hay making. 



From prior considerations, it would be natural to presume that the 

 processes of hay and silage making would result in a diminution of the 

 digestibility of the ingredients of the green forage, since it seems reason- 

 able to assume that whatever fermentative or bacterial changes take 

 place, do so mainly at the expense of the more readily assimilated con- 

 stituents. The characteristic change which occurs when green forage is 

 packed into the silo involves the destruction of carbohydrates with the 

 formation of organic acids, hke lactic and acetic acids. This is the result 

 of fermentation mainly brought about by the enzymes of the plant cells 

 and by bacteria. Since the more ea.sily assimilated carbohydrates are 

 hable to be used up in this process, it would be anticipated that the 

 residual carbohydrate ingredient of the silage would have a diminished 

 digestibiUty. On the other hand, the percentage of digestible ether 

 extractable material in the forage will be augmented by the formation 

 of the organic acids, although the net result of the change must involve 

 loss of nutritive value. This loss, however, need not necessarily, on theo- 

 retical grounds, be considerable, since these changes are quickly arrested 

 after the development of a sufficient degree of acidity. In any case, it 

 should be remembered that all types of roughage suffer similar destruction 

 of soluble carbohydrates during the time they stagnate in the rumen of 

 the animal. 



1 Amos, Journ. of the Farmers' Chih, Part 2, 1920. 



