124 SCIENTIFIC FEEDING OF ANIMALS 



is practised, in which the plants are allowed to 

 wither after cutting, and are then made into 

 stacks, or stored in barns. The various modifica- 

 tions which are adopted differ considerably as 

 regards the drying of the grasses, etc. It is prefer- 

 able to continue the drying until the plants begin 

 to rustle when they are handled, but the leaves 

 should remain tough and not brittle, and the stems 

 green but containing little sap. The hay is then 

 carted to the stack, or left for a day or two in the 

 field in cocks. In making the stack, the hay is put 

 on in layers and trampled down so that no cavities 

 remain, for in them moulds would form. The 

 stacks are afterwards usually covered with a thatch 

 of straw. After some little time, in some cases 

 even twelve hours, fermentation, accompanied by 

 a rise of temperature, sets in. In the interior of 

 the stack, the temperature rises to 100-140 F., 

 even 202 F., but it should not be allowed to go 

 above 175 F. Sometimes the heating of a stack 

 goes so far that there is danger even of it taking 

 fire, but in any case the temperature should not be 

 allowed to rise too high, for otherwise the quality 

 of the hay suffers. The cutting of holes into the 

 stack, or the taking off of some of the hay, are the 

 methods usually adopted to cool down the mass. 



The heating of the hay is due to several causes, 

 such as the respiration of the still living parts of 

 the plants, the combination of oxygen enclosed 



