322 POULTRY PRODUCTION 



Combinations of Feeds. — Some feeds are more digestible 

 when combined with certain other feeds than when fed 

 alone. Thus Bartlett' found by combining 7 per cent bone 

 meal with a ration made up of 200 pounds bran, 50 pounds 

 corn meal, 50 ])ounds linseed meal, and 100 pounds gluten 

 feed the organic matter was rendered 4.6 per cent more 

 digestil)le. 



Sometimes combining certain feeds adds to the palata- 

 bility, thereby inducing a greater consumption of feed, but 

 not actually rendering the feed consumed more digestible. 

 This is very possibly the case in adding salt to the ration. 



Kalugine (as reported by H. J. Wheeler") is authority for 

 the statement that fine gravel, when fed in combination 

 with a ration, increases the coefficient of digestibilitj' of the 

 nutrients. 



Amount and Frequency of Feeding. — There is no direct 

 experimental evidence bearing on these points. There is 

 no reason to believe, however, that, even taking into account 

 the involuntary grinding on the part of the fowl, poultry are 

 an exception to the rule for other animals, that when large 

 amounts of food are consumed the work of the digestive 

 tract is not so thorough and the coefficients of digestion of 

 at least some of the nutrients will be smaller. With other 

 animals this difference is noted with all food constituents 

 exce])t fat.-' 



There appears to be small probability that the frequency 

 of feeding affects digestibility appreciably. 



Nutrients from Vegetable and Animal Sources. — As will be 

 seen by reference to the table of digestion coefficients for 

 poultry, protein in all cases, and fat in most cases, is more 

 digestible when sup])lied from animal sources than from 

 vegetable sources. These coefficients are borne out by 

 l)ractical experience and by feeding experiments generally. 

 With particular reference to protein Ilartwell and Kirk- 

 patrick* found that beef scraps and milk albumin showed 

 a marked superiority over cottonseed meal, linseed meal, 



' Maine Bulletin No. 184. ' Rhode Island Rulletin No. 84. 



^ Kcllncr, TJie Scientific Feerling of Anim.^I3. 

 ' Rhode Island Hulletin No. 45. 



