CIECUMSTANCES AFFECTING DIGESTIBILITY. 105 



of meat flour were afterwards added: the albumi- 

 noids of the meat were entirely digested, while 

 the proportion of the potatos digested remained un- 

 changed. 



An addition of oil (olive, poppy, and rape oil) to a diet 

 of hay and straw is also apparently without unfavourable 

 influence on the rate of digestion ; indeed some experi- 

 ments with small quantities of oil (Jib. of oil per day per 

 1,000 Ibs. live weight) show an improved digestion of the 

 dry fodder. Oil supplied in moderate quantities is itself 

 entirely digested. 



An addition of starch or sugar to a diet of hay or 

 straw will, on the contrary, diminish its digestibility, if 

 the amount added exceeds 10 per cent, of the dry fodder. 

 The albuminoids of the food suffer the greatest loss of 

 digestibility under these circumstances; the fibre also 

 suffers in digestibility if the amount of carbo-hydrate 

 added is considerable. When starch has been added, it 

 is itself completely digested, if the ratio of the nitro- 

 genous to the non-nitrogenous constituents of the diet 

 (seepage 111) is not less than 1 : 8. 



These facts are of considerable practical importance. 

 Nitrogenous foods, as oilcake and bean meal, may be given 

 with hay and straw chaff without affecting their digesti- 

 bility ; but foods rich in carbo-hydrates, as potatos and 

 mangels, cannot be given in greater proportion than 15 

 per cent, of the fodder (both reckoned as dry food) with- 

 out more or less diminishing the digestibility of the latter. 

 This decrease in digestibility may, however, be counter- 

 acted in great measure by supplying with the potatos 

 or mangels some nitrogenous food. When this is done 

 the proportion of roots or potatos may be double that just 



