82 



THE SCIENTIFIC FEEDING OF ANIMALS 



was attached (size 8 to 13 by 2 to 3 mm.). These two grains are inclosed 

 in common by two large glumes which usually remain attached to the 

 straw when threshed. In the awned varieties of oats the lower main 

 grain only is supplied with an awn. The main grains are frequently 

 separated from the threshed product by special machines and used for 

 seed. 



According to the degree of development of the oat grains they are 

 classified as plump, medium, lean, and screenings, or first, second, third 

 and fourth grade. In plump grain (first grade. Figs. 39 and 40) the 

 inner glume bulges or is convex. In medium or second grade grain this 

 glume is flat. In lean or third grade grain it is hardly visible, and in 

 screenings or fourth grade grain the borders of even the outer glume are 

 curled inward. A cross section, at the largest diameter, of plump grain 

 is oval in form, and dorsal and ventral surfaces convex to an almost equal 



(32 ^ 



a, bed 



Fig. 39. Ventral surface of different 

 oat grains, a, plump or full grain ; b, 

 normal or medium grain; c, lean grain; 

 d, screening grain. 



Fig. 40. Cross sections of different oat grains. 

 Plump or full grain; h, normal or medium grain; 

 lean grain; d and e, screening grain. 



degree. Medium grade grain thus sectioned shows a flattened ventral 

 surface, lean grain a kidney shaped outline, and screenings or fourth 

 grade grain shows an irregular figure which consists chiefly of glumes 

 (sterile grain). In medium grade or normal grain the glumes should 

 exceed the grain by not more than one-quarter of its length. In poor 

 grades of oats the glumes are considerably longer. 



The weight of the glumes or hulls of oats vary between 21 and 49 

 per cent. In fine hulled varieties it is usually under 26 per cent and in 

 coarse hulled varieties it is usually over 29 per cent. Long glumes and 

 sterile grains tend to increase the percentage weight of the hulls. The 

 German army regulations require that oats may contain a maximum of 

 30 per cent glumes or hulls. 



The following table gives the chemical constituents of the more val- 

 uable grain proper and of the less valuable hulls, of the oat. 



