390 The Feeding of Animals 



food proved much more efficient than those of vege- 

 table origin, the latter having, according to the ordi- 

 nary methods of estimation, the same nutritive value 

 as the former. 



It seems probable that the ash constituents have 

 sometimes not been sufficiently considered in feeding. 

 While the importance of the mineral nutrients can be 

 largely overlooked without serious practical disadvan- 

 tage when feeding some animals for certain purposes, 

 it must be given consideration when feeding domestic 

 fowls. While in milk, for instance, about 5 per cent 

 of the dry matter is ash, in eggs over 35 per cent 

 of the dry matter is represented by the mineral con- 

 stituents. 



The shell of the egg, which represents about 11 

 per cent of the fresh egg, consists almost entirely of 

 carbonate of lime. Most grain foods which naturally 

 constitute the bulk of ordinary rations contain little 

 mineral matter and the amount of lime is notably 

 low. For simply supplying the deficiency of material 

 for the egg shell, carbonate of lime in the form of 

 oyster shell can be used. This was shown in experi- 

 ments at the New York Experiment Station made 

 with laying hens after they were closely confined on 

 a clean floor for over three weeks. It was then found 

 that about nine -tenths of the lime in the egg shell 

 was unaccounted for in the food aside from the oyster 

 shells which were fed. 



While less than 10 per cent of the body of a 

 fowl is mineral matter, it consists largely of phosphate 

 of lime and exceeds in proportion that of many foods. 



