FOODS. 



83 



not digest more by being starved. Labour also is practi- 

 cally without influence, horses at rest and at work digesting 

 nearly the same proportion of their food. Differences in 

 the quality of a food may, however, exercise a great 

 influence on its digestibility ; the addition of another food 

 may also considerably alter the rate of digestion of the 

 first food. 



The digestibility of fodder plants is mainly determined 

 by their age ; all the constituents of a young plant are 

 more digestible than in the same plant of greater age. 

 The composition of meadow grass cut at three different 

 dates has been already given on page 74 ; this grass was 

 supplied to sheep in the form of hay, and yielded the 

 following digestion coefficients : — 



DIGESTION OF HAY BY SHEEP. 



The diminution in digestibility with the increasing 

 maturity of the grass is very striking, and is very equally 

 spread over all the constituents. Similar experiments 

 with clover cut at different stages of growth have yielded 

 similar results. It follows plainly from what has been now 

 stated that no fixed nutritive value can be applied to 

 fodder crops, or to the hay made from them, as both their 



