272 



Journal of Agricultural Research 



Vol. XV, No. 5 



usually results in depressing the digestibility of these ingredients. If it 

 be assumed that the starch was completely digestible — that is, if all the 

 effects just mentioned be assigned to the hay — the digestibility of the 

 latter as compared with that observed in the periods when the hay was 

 fed alone was as shown in Table IV. 



Table TV .—Influence of starch on digestibility of hay 



In some respects a more rational method of expressing this depression 

 in digestibility is in terms of the actual amounts instead of the percentages 

 of the various ingredients. Table V shows the number of grams by 

 which the several nutrients actually digested from the mixed ration of 

 periods i to 4 differ from what would be expected on the same assump- 

 tion as in Table IV. 



Table V. — Depression of digestibility by starch 



Period No. 



3- 

 2. 



4 



Total 

 nitrogen. 



Gm.. 

 16. o 



9-5 



4.4 



3-6 



INFLUENCE OF QUANTITY OF FEED ON DIGESTIBILITY 



The figures of Table III show a distinct influence of the quantity of 

 feed upon the percentage digestibility, as has been the case in most pre- 

 vious experiments.^ The digestibility increases as the amount consumed 

 is decreased, although the differences are relatively small. To this rule 

 period 3 constitutes a distinct exception. As will appear, the results of 



' Armsby, H. p. the nutrition of farm animals, p. 613-618. New York, 1917. 



and Fries, J. A. energy values of hominy feed and maize meal for cattle. In Jour. Agr. 



Research, v. 10, no. 12, p. 605. 1917. 



. INFLUENCE OF the DEGREE OF FATNESS OF CATTLE UPON THEIR UTILIZATION OF FEED. 



/n Jour. Agr. Research, v. 11, no. 10, p. 453. 1917. 



and Braman, W. W. energy values of red-clover hay and maize meal. In Jour. 



Agr. Research, v. 7, no. 9, p. 381. 1916. 



