22 SOURCES OF LOSS IN FERMENTATION. 



Dr Heiden states that the amount of straw used as 

 litter for the horse in Germany is between 4 to 6 Ib. 

 per day. The quantity should be regulated according 

 to the percentage of water the excreta contains ; the 

 more watery excreta requiring naturally a larger 

 quantity of litter. The most eminent authorities on 

 this subject recommend that the amount of litter 

 should equal one-fourth of the food in its natural 

 state, or about one-third of its dry substance. 



The second source of loss, which is due to volatilisa- 

 tion of the volatile ingredients, may be largely pre- 

 vented by the use of certain preservatives. 



Horse-dung being, comparatively speaking, of a dry 

 nature, it is extremely difficult to effect its thorough 

 mixture with the litter. For this reason the manure 

 formed from horse excreta is particularly liable to 

 rapid fermentation. 1 In the process of fermentation, 

 as will be seen more in detail further on, the nitrogen 

 is converted into carbonate of ammonia. As nitrogen 

 in this form is of an extremely volatile nature, the 

 risks of loss from this source are considerable. As 

 illustrating this fact, it may be mentioned that Bous- 

 singault has found by experiment that the total per- 

 centage of nitrogen contained by fresh horse -manure 

 might be reduced in the process of fermentation to one- 

 half of its original amount by loss from this source. 



1 The rapid fermentation of horse -manure is due to its mechanical 

 as well as its chemical nature. The horse does not reduce its food 

 to such small pieces, and its urine is rich in nitrogen. 



