MEAT PRODUCTION 447 



the fattening might consist exclusively of non-nitrogenous 

 nutrients. 



526. Influence on digestibility. In the actual compound- 

 ing of rations for fattening, however, whether for mature or for 

 growing animals, account must be taken of the fact that such 

 a considerable addition of non-nitrogenous nutrients to a 

 maintenance or growth ration may have an unfavorable effect 

 upon its digestibility. In particular, it has been shown (723) 

 that a large proportion of easily digestible carbohydrates in a 

 ration (i.e., a " wide " nutritive ratio) tends to depress the 

 apparent digestibility of the protein. Accordingly, if, starting 

 with a ration just adequate to support the normal rate of growth, 

 the attempt be made to convert it into a fattening ration by 

 simply increasing its digestible carbohydrates, the effect may be 

 to virtually diminish the amount of protein available so that 

 the ration, while containing abundant material for fat produc- 

 tion, may fail to supply enough protein to utilize fully the 

 animal's capacity for growth. 



The increase due to growth, however, is an important factor 

 of the cheaper gains made by immature animals (509). In in- 

 creasing the total feed supply in order to secure the fattening 

 of the young animal, therefore, it is important to avoid the dan- 

 ger of so decreasing the apparent digestibility of the protein 

 by the too free use of feeding stuffs rich in carbohydrates as to 

 reduce the protein supply below that needed for growth. More- 

 over, it has been found (723-727) that a relative deficiency of ni- 

 trogenous matter in a ration also decreases the digestibility 

 of the carbohydrates, particularly of those less soluble forms 

 which are acted upon chiefly by the fermentative processes in 

 the rumen or ccecum, and so tends to reduce the energy value 

 of the ration. 



It is difficult, however, to make any very definite statements 

 regarding the practical significance of these effects in actual 

 feeding. Kellner recommends that the nutritive ratio (709) of a 

 fattening ration, computed in the usual way, be not made wider 

 than about 1:8-9 f r cattle and sheep and 1:10-12 for 

 swine. Ordinarily, there will be little difficulty in compound- 

 ing rations conforming to this rule, especially when home grown 

 protein feeds are available, and such rations when fed in suf- 

 ficient amounts to support reasonably rapid fattening would 



