202 FEEDING STUFFS 
birds, provides ash for the skeleton. It seems to be of less value 
for growing chicks, as it contains little if any phosphate. Samples 
of crushed oyster shells usually run over 95 per cent carbonate of 
lime. Crushed shells are especially valuable when they can be fed 
fresh, that is, gathered regularly from the beach, or after the oysters 
or clams have been removed, and immediately crushed or ground. 
Sources of Phosphate-—Composition (pounds in 100). 
Phosphoric acid, 
Protein. P2035. 
Granulated bone (dry)...................5.. 25 24 
Green cut bone..........0... 00.00 cece eee 19 to 34 =. 23 to 25 
Phosphate Tock, «0.04 5.00. ee ee eben ca ae ie 28 to 32 
Poultry grit is not valuable as a source of ash, as it usually 
contains little if any lime, and very little phosphate, the main 
component being silica. The function of grit is that of grinding. 
Other Sources of Mineral Matter—There are a great many 
advertised sources of mineral matter for poultry feeding. Few of 
the commercial forms, however, seem to supply the particular 
kind of mineral in the best form. Raw phosphate rock gives fair 
results, but the available mineral matter is small in comparison 
with its bulk. There are certain advertised commercial feeds 
which are guaranteed to contain a large quantity of ash. Some 
of these, owing to their physical properties, are of little value, 
and are not economical when compared with the results obtained 
by the use of cheaper and better-known materials, such as bone 
products. 
Ash in Grains——Wheat bran is a very efficient source of ash 
and is fed quite extensively with this purpose in view. Consider- 
ing only its value as a protein carrier, the cost of wheat bran is 
relatively high, but considering its palatability and high ash con- 
tent it can be highly recommended. It is desirable in the feeding 
of baby chicks. There are other grains, such as barley and oats, 
which contain enough ash to be worth considering. 
Double Function of Minerals—Experiments show that the ash 
content in a ration bears a definite relation to the complete use 
of other nutrients in it. Not only is the actual availability of the 
mineral matter itself of value, but mineral compounds have a 
very noticeable effect in increasing the digestibility of other 
nutrients in the ration, especially protein. Minerals thus perform 
a double function. 
