1912.] PUBLIC DOCUMENT — No. 31. 15 



White Cap Yellow, Brewer's,^ Early Mastodon^ ). The very 

 coarse late-maturing varieties w^hich never ripen seed in this 

 locality are not satisfactory for silage purposes. 



3. As is well known, the season has a marked influence on 

 the yield of the corn plant, the same variety under otherwise 

 identical conditions yielding from 50 to 100 per cent, more in 

 a year particularly favorable to its growth. 



4. The changes in chemical composition which the corn 

 plant undergoes in its development are such that its maximum 

 feeding value exists at its maturity. 



5. Numerous digestion experiments have shown no wide 

 variations in the digestibility of the several varieties, the 

 range being from 67 to 77 per cent, with an average of ap- 

 proximately 70 per cent. The general statement can be made 

 that the higher the percentage of extract or starchy matter 

 present (the larger the percentage of ears) the higher the 

 digestibility and resulting feeding value. 



6. The percentage of grain to cob varies widely, depending, 

 to some extent, upon the maturity of the plant when cut. The 

 average for the several mature types was 15.5 per cent, cob 

 and 84.5 per cent, kernel, while the average for the less mature 

 varieties was 18.1 per cent, cob and 81.9 per cent, kernel. 

 In either case the percentage of cob was less than that of the 

 legal Massachusetts bushel, which in case of shelled corn is 

 56 pounds and in case of ear corn 70 pounds, thus allowing 

 14 pounds or 20 per cent, for cob. 



7. The grain showed only slight variations in composition. 

 It is believed that chemical composition cannot be considered 

 an important factor in the selection of seed corn when the 

 crop is to be used for the sustenance of live stock. 



8. But little variation was noted in the composition of the 

 corn cob. The net available energy in 100 pounds of cob is 

 40.2 therms, as against 85.5 therms in a like amount of corn 

 meal ; hence the cob has 47 per cent, of the value of the meal 

 for feeding purposes.^ 



• Do better in southern New England. 



' This is calculated on the basis of the method suggested by Kellner, and is the most satisfac- 

 tory method available for the estimation of relative energy values. 



