420 NUTRITION OF FARM ANIMALS 



has shown the same thing to be true of a variety of organic 

 phosphorus compounds, as well as of the phosphorus of con- 

 centrated feeding stuffs, while in case of roughages l an avail- 

 ability of approximately 50 per cent was observed. These 

 facts throw some doubt on Kellner's conclusion that the feed 

 should contain two or three times the quantities of mineral 

 elements which would normally be stored in the body. 



496. Effects of deficiency of ash. But while it seems 

 scarcely possible to make any definite quantitative statements 

 regarding the necessary ash supply of growing animals there is 

 abundant evidence of the evil effects of an insufficient supply. 

 In particular, a deficiency of calcium, as already indicated, 

 may have serious consequences both directly and on account of 

 the fact that such a deficiency generally connotes an acid ash 

 (431). 



Kellner 2 cites experiments by Roloff and by Voit, in which young 

 dogs and pigs receiving feed poor in calcium showed deficient growth 

 and developed severe pathological symptoms, the skeleton showing 

 a notable deficiency in ash ingredients (Rachitis) . Forbes 3 has col- 

 lected a large number of experiments on this subject in some of which 

 marked effects on the composition of the bones were observed while 

 in others these effects were not very distinct. In still more recent 

 experiments by Weiser 4 upon pigs, a diet deficient in calcium re- 

 stricted the growth and produced a skeleton containing an excess of 

 water and organic matter and deficient in ash. Contrary to the re- 

 sults of Aron (428) the bone ash on the calcium-poor rations was 

 deficient in calcium and contained an excess of alkalies, especially 

 sodium. 



Of farm animals, pigs are most likely to suffer in this way, 

 partly because their growth is relatively rapid and partly be- 

 cause they often receive almost exclusive grain rations which 

 are apt to be low in calcium (431). Henry 5 has shown that 

 supplementing such rations with calcium phosphate or car- 

 bonate results in the production of heavier and stronger bones, 

 and Burnett 6 has confirmed these results. Hart and McCol- 



1 Biochem. Ztschr., 37 (191 1), 266. 



2 Ernahrung der landw. Nutztiere, 6th Ed., p. 177. 



3 Ohio Expt. Sta., Tech. Bui. 5, pp. 384-390- 



4 Biochem. Ztschr., 66 (1914), 95- 



6Wis. Expt. Sta., 6th Rpt., pp. 6-41 ; Bui. 25. 

 6 Neb. Expt. Sta., Buls. 94 and 107 and 23d Rpt. 



