134 
Journal of Agricultural Research 
Vol. XIV, No. 3 
In the eighth period 40 per cent of the potassium, 70 per cent of the 
sodium, 25 per cent of the calcium, 2 per cent of the magnesium, 32 per 
cent of the sulphur, 51 per cent of the chlorin, 24 per cent of the phos¬ 
phorus, and 63 per cent of the iron were supplied by the sour skim milk. 
If we consider the total mineral nutrients that would have been 
supplied by the feed ingested, leaving out the milk, there would have been 
ample furnished in any of the eight periods. 
If the birds had received neither milk nor mash, there would have 
been a deficiency in the first period in all mineral elements except potas¬ 
sium and magnesium provided that the same quantity of feed was 
consumed as a grain mixttlre and that the consumption of shell or lime¬ 
stone as grit was not considered. In the second period there would 
have been a deficiency in sodium, calcium, potassium, and iron. In 
the third period there would have been a deficiency in sodium, cal¬ 
cium, phosphorus, and iron. In the fourth period there would have 
been the same deficiency as in the third period. In the fifth, sixth, and 
seventh periods there would have been a deficiency in calcium alone, 
and a deficiency in calcium, sodium, and phosphorus in the eighth 
period. 
In Table IX there is an apparent balance of calcium of 20 gm. un¬ 
accounted for, and in this connection it must be remembered there 
would be at least 1 or 2 gm. of limestone grit per bird still remaining 
in the gizzards at the end of these tests. This would likewise affect the 
magnesium, leaving a small balance, and the same holds good for the 
iron, since the limestone used in these experiments contained 3 per cent 
of iron. The summary of the eight periods indicates an apparent shortage 
of phosphorus and a slight shortage of magnesium. 
To supply the proper amount of phosphorus, magnesium, and calcium 
to growing chicks, in mashes consisting of such mill feeds as middlings 
and ground oats there should be added meat and bone meal, or bone 
meal, or meat meal. Sour skim milk and buttermilk, if given in suffi¬ 
cient quantities, aid in making good the mineral shortages as well as 
providing food hormones, which have a stimulating effect upon the growth 
of the young, as shown by work in this and other laboratories. 
SUMMARY 
The mineral content of southern poultry feeds varies in different kinds 
of feed and in different lots of the same kind. This difference is influ¬ 
enced by weather conditions, such as drouth, and by the different 
mineral contents of the soil. # 
In the development of the broiler from the baby chick there is a 
gradual increase in the requirements of calcium, magnesium, phosphorus, 
and sulphur. To supply this increase and to attain the best growth' 
there must be added to a ration consisting of mill products and ground 
grain, such products as meat meal, bone meal, meat and bone meal, and 
sour skim milk or buttermilk. 
