54 PRINCIPLES OP FEEDING FARM ANIMALS 



for a series of years, LeClere found that the climatic environment 

 (i.e., temperature, rainfall, and sunlight) is the most important 

 factor that influences the physical and chemical characteristics of 

 a crop, 1 and the results obtained by Wiley with sugar beets and 

 sweet corn lead to the same conclusion. 2 



The length of the growing periods of plants is another factor 

 that influences the quality of the crop grown. Spring grains are 

 higher in protein and lower in starch than winter grains, because 

 their growing period is shortened by the higher average temperature 

 during the summer. Plants grown in the South are richer in 

 protein than northern-grown plants, for the same reasons. 3 



The Variety and Quality of Seed. — The sowing time and the 

 method of seeding or planting are other factors that have a bearing 

 on the quality of the crops grown. The stage of development when 

 a crop is harvested is another factor that influences profoundly both 

 the crop yields secured and their chemical composition and feeding 

 value. We select as illustrations data obtained with two of the 

 most important single forage crops in our country, Indian corn 

 and alfalfa. 



Indian Corn. — Like all other plants, Indian corn is higher in 

 water, ash, protein, amides, and fat, and lower in starch and fiber, 

 during early vegetative stages than later during the growing period. 

 In experiments conducted by Hornberger, a field of Indian corn 

 was sampled and analyzed once every week, from June 18, when 

 the plants were only six to seven inches high, until September 10, 

 when the com was nearly ripe. The results of the analyses show 

 that the water contents of the samples decreased with the advance 

 of the growing period from 90.3 per cent to 80.5 per cent, and 

 that the ranges in composition of the dry matter were as follows : 



Ash from 9.5 to 4.3 per cent. 

 Protein from 30.8 to 9,7 per cent. 

 Amides from 9.8 to 2.8 per cent. 



Fiber from 17.8 to 22.6 per cent (with a maximum of over 26 per cent, 

 August 6 to 13). 



Nitrogen-free extract from 41.7 to 61.5 per cent. 

 Fat from 3.2 to 1.6 per cent. 



Considering the total yields of feed components on the different 

 dates, the following results are worthy of special note :* 



1 Journal Agricultural Research, i, p. 275. 



2 Bulletins 96 and 127, Bureau of Chemistry, U. S. Department of Agri- 

 culture. See also Shaw, " Studies upon the Influences Affecting the Protein 

 Content of Wheat," Univ. of Cal. Pub. in Agricultural Sciences, No. 5. 



"Haselhoff, "Landw. Futtermittel," p. 13. 



4 See Woll, " A Book on Silage," Bxv. Ed., p. 14. 



