278 EXPERIMENT STATION RECORD. 



weeks. The average gain of the ducks fed animal food was 5.3 lbs., 

 of those fed vegetable food and bone ash 3.3 lbs., 3.3 lbs. of food, 

 costing 8.5 cts., and 4.3 lbs. costing 4.1 cts. being required per pound 

 of gain, respectively. Two lots of about 14 laying hens were used for 

 further testing the 2 rations. The test covered 210 days. The aver- 

 age egg production of the hens fed animal food was 119.4 eggs; of 

 those fed vegetable food and bone ash, 112.7 eggs, the dry matter 

 required per pound of eggs being 3 and 3.2 lbs., respectively. The 

 cost of food per pound of eggs was 3.2 cts. for each lot. When tested 

 for fertility the eggs from the former lot were, in the author's opinion, 

 better from a breeder's standpoint. No difference, however, in the 

 vigor of the chickens hatched from the eggs of the 2 lots was observed. 

 The author summarizes his experiments and the deductions drawn from 

 them as follows: 



"In general, rations containing animal food appear more palatable than rations of 

 somewhat similar chemical composition consisting wholly of vegetable food. Rations 

 in which the lack of palatability was overcome by using an unusual variety of grain 

 foods were inferior for growing chicks and laying hens and decidedly inferior for 

 ducklings to rations in w'hich nearly one-fifth of the dry matter was supplied by ani- 

 mal food. After the period of most rapid growth had passed and the young birds 

 approached maturity the difference in the efficiency between such rations rapidly 

 disappeared. ... 



"Although it was foimd possible, when using a large number of foods in contrasted 

 rations of these kinds, to have the ordinary groups of organic compounds in approx- 

 imately equal proportions, there was always a much larger amount of mineral matter 

 in the one ration owing to the bone of the animal meal. So there was sometimes 

 nearly three times as much phosphorus in the one ration as in the other. . . . 



"From these results it appears that rations containing a necessary amount of pro- 

 tein and having the relation of the ordinarily 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 extent 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 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 eflaciency a ration containing animal food by supplementing it 

 with suitable mineral matter, there are plain limitations to its economical use. For 

 laying hens some animal food appears necessary for continued good results. Duck- 

 lings 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 as.sumed deficiency in one ration 

 and proved an efficient addition for the purpose, it should not be inferred that its 

 purchase for feeding is to be generally recommended. It was necessarily used to 

 oVjtain information. 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 w'hich 

 food it constitutes an important part. In some instances, of course, dry bones, 

 where no facilities exist for grinding, or green bones in questionable condition, can 

 be safely and economically used when charred or reduced to ash. The very desira- 

 ble organic matter associated with fresh or cooked bones should not be wasted." 



