336 TeiiijK ridnrc tijf'crfing the Quality of Sihuje 



of juice are liable to drain away from the silage and carry with them 

 soluble food material, which if allowed to accumulate in the yard under- 

 goes fermentation and ])r()duces a smelly mass of putrid material, if, 

 however, the juice is collected cattle and pigs readily drink it. This 

 problem is receiving further study. 



{d) Sour silage is j)roduced under at least two different sets of con- 

 ditions. It may be ])roduced from an immature and succulent crop, or 

 it may be produced from a crop which has been cut and then saturated 

 by rain before ensiUng, especially when the crop has become laid and 

 partially rotten at the base before cutting. 



Sour silage has a dark brown or olive brown colour witli a pungent 

 and most un])l('asaiit smell ])ossibly due to butyric acid. Cattle will 

 eat this, but not readily and do not generally thrive upon it. 



(e) Musty silage. One case only of tliis type had been recorded, in 

 which an over-ripe crop containing much charlock was allowed to wilt 

 and become over-dry before ensiling. A number of tiny mouldy centres 

 were produced in which ammonia was generated. 



This silage has a dark bro\\ii almost black colour and has a musty 

 ammoniacal smell. Stock refused to eat it or ate it only under com- 

 2)ulsiou. 



3. The classiiication of silages given ai)ove is admittedly superficial, 

 but it may serve to pave the way for the chemist, the plant phj^siologist 

 or perhaps the bacteriologist to produce similar types of silage under 

 well defined conditions and so make the distinctions more absolute. 

 For the successful practice of ensilage in this country it is fundamental 

 that the conditions by which each type of silage may be produced should 

 be accurately known. 



4. In the past persons conducting feeding experiments in this 

 country have rarely attempted to define the type of silage used, and 

 conflicting results have been obtained. When it is further noted that 

 the quality of silage at different parts of a silo may be, and frequently 

 is, fundamentally different, it is of the utmost importance that these 

 facts should be recorded in future feeding experiments. 



Our acknowledgements are due to the Ministry of Agriculture who 

 have financed this study, to Messrs English Bros, of Wisbech who 

 generously i)resented the experimental silo and to Prof. Biffen and his 

 farm managers Messrs TI. Y. Sliei-ingham and N. Langridge who have 

 facilitated the ex])eriments u|ion tin- Plant Breeding Farm at Cambridge. 



(Received August 7th, I92"2.) 



