124 Report of the Department of Animal Husbandry. 



considered constituents satisfactory may be inferior because of a 

 lack of mineral matter, probably phosphates. 



Not enough data are now available to show to just what ex- 

 tent the deficiency of lime in the food for the younger chicks may 

 have been responsible for inferior results. With laying hens, lack 

 of lime could not have affected the results considered; for oyster 

 shells were freely supplied, and it has been shown (see Bulletin 

 ISTo. 38) that such material can make good the frequent deficiency 

 of lime. 



It appears also that, while a cheaper vegetable food ration can 

 sometimes be made to equal or surpass in efficiency a ration con- 

 taining animal food by supplementing it with suitable mineral 

 matter, there are plain limitations to its economical use. For lay- 

 ing hens some animal food appears necessary for continued good 

 results. Ducklings without an abundant supply of animal protein 

 in the ration, together with a liberal proportion of mineral matter, 

 seem unable to make any approximation to their normally rapid 

 and most profitable growth. 



Although bone ash was used to make good an assumed defi- 

 ciency in one ration and proved an efficient addition for the pur- 

 pose, it should not be inferred that its purchase for feeding is to 

 be generally recommended. It was necessarily used to obtain in- 

 formation. Bone ash in the market is expensive. The same 

 amount of mineral matter can be obtained much cheaper in fresh 

 bone or animal meal, of which foods it constitutes an important 

 part. In some instances, of course, dry bones, where no facili- 

 ties exist for grinding, or green bones in questionable condition, 

 can be safely and economically used when charred or reduced to 

 ash. The very desirable organic matter associated vnth fresh or 

 cooked bones should not be wasted. 



