THK FEKDINO OF TIIK ANIMAL 249 



oiii'-!iaU' poiiiuls of digestible heat and t"at- 

 foniiing elements. A ratio is said to be wide or 

 narrow wlien tlie projwrtion of heat-forming 

 nutrients is large or small in proportion to the 

 protein. Thus, 1: \'2 is widtM- than 1: 7. 



•\'i\. A ••.Ttaiii }>n»p<ii-tinii sjiould »'.\ist lictween 

 th«' nitrogenous and n»>n-nitrogenous nutrients of 

 a ration. Animals that an* growing rai)idly, that 

 are bearing young, and that aro i>ro<lucing wool, 

 milk or egi^s, require a more nitrogenous food 

 than animals that are working, or fattening, or 

 living without gain (»r loss of weight. For the 

 lattt-r, tilt' nutritive ratio may bt> as wide as 1: 12 

 or 1:14; for the former, tli<' nutritive i-atio should 

 be as narrow as 1 : .'> or 1: li. 



i'>'). Formerly it was su]>posed that slightly 

 ditTeriiig nutritive ratios would make distinct 

 dilTei«'nees in the (»tTectiveness of a ration or the 

 quality of the j)roduet ; but it is now generally 

 considered that the limits of variation in the 

 nutritive ratio may bf rather wide without iiuite- 

 rially intlueneing the nutritive etTe«'t of the 

 ration. Otlu'r (•on<litions may mask the effect 

 (hie to dilTerenees in the nutritive ratio. 



4.')J. One of the chii'f reasons for taking the 

 nutritive ratio into consideration is that the i>ro- 

 tein may l>o economically used. Protein sliould 

 be used for the formation of nitrogenous pro<inc't8 

 in the animal. It mav, however, be used n-^ a 



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