COARSE DRY FODDERS 259 



and the rate of development of each ; and these, in turn, 

 depend largely upon the age of the lea, climate, season, soil, 

 and manuring. At all events, whatever the causes, it is clear 

 that the proportion of undergrowth to flowering plants must 

 have a considerable effect upon the composition and properties 

 of the final product. 



Various changes set in rapidly as soon as the grass is cut. 

 The most obvious, and in many respects the most important, 

 is the evaporation of water. The rate of evaporation depends 

 upon the temperature, dryness of the atmosphere, wind, and 

 the total bulk of produce. It is, therefore, very variable, 

 but under favourable conditions it takes place very rapidly. 

 In warm climates hay is sometimes cut in the morning and 

 stacked the same night. In this country it is sometimes not 

 dry enough to stack after a week's exposure. 



It is well known in another connection that evaporation 

 of water produces a bleaching, i.e. an oxidising action. 1*he 

 colour of the grass is, therefore, always much reduced. If 

 the material is wet and dried again several times, the colour 

 is entirely bleached. At the same time, fermentative changes 

 occur, and a large proportion of the carbohydrates, which 

 are present as insoluble compounds in the grass before it is 

 cut, are rapidly resolved into soluble substances sugars, 

 mucilages, etc. Aromatic compounds, which give the hay 

 a pleasant odour, are also formed. If the hay is wet by rain 

 after these changes have taken place, much of the soluble 

 and aromatic substances is dissolved and washed out. The 

 soluble compounds which are thus lost are, of course, the 

 most readily digestible nutrients. In some experiments made 

 by the author as much as 20 per cent, of the nutrients present 

 in the fresh grass were lost by weathering. The loss of colour 

 and aroma are evidence of this deterioration. The growth 

 of moulds, which cannot afterwards be got rid of, is an 

 even more objectionable result of the weathering. These 

 organisms, even in small quantity, are evidently very dis- 

 tasteful to the animals and are liable to prove injurious. The 

 quality of hay depends more largely upon the condition in 

 which it is " got " than upon any other single circumstance. 



