208 PRACTICAL POULTRY PRODUCTION 



by multiplying the fat by 2^. (Fat has 2^ times as much 

 heat value as nitrogen-free extract.) 



Up to this time sufficient experiments have not been 

 carried on in feeding poultry to determine the amount of 

 various feeds that are actually digested by poultry, as has 

 been done with cattle. The total composition of feed stuffs, 

 therefore, will be used in computing the nutritive ratio 

 rather than the percentage of digestible nutrients. The 

 nutritive ratio, as will be given below, will not include the 

 fiber content, as very httle fiber is digested by poultry. The 

 composition of the various poultry feeds is shown in Table II. 



How to determine the nutritive ratio. The following 



Figure 206. — Various styles of drinking fountains. 



will illustrate how a nutritive ratio is determined. Ration 

 No. 3 as found on page 212 will be selected for this purpose, 

 as it consists of but four ingredients, and the simphcity 

 of its make-up will enable one to see how a nutritive ratio 

 is computed more quickly perhaps than a complicated ration. 

 Referring to Table II will be found the number of pounds 

 or per cent of the several feed constituents in 100 lbs. of 

 each of the feeds Usted. In order to get the number of 

 pounds or per cent of these constituents in 2 lbs. of cracked 

 corn, the per cent of protein, nitrogen-free extract, and fat as 

 given in Table II for cracked corn is divided by 100 to get 

 the amount in 1 lb., which is then multiplied by 2 lbs. This 

 same procedure is followed out in each of the other 3 in- 



