Observations on the mineral metabolism of pullets. III

Abstract

1. An experiment on pullets combining daily calcium and phosphorus balance determinations with carcass analyses is described.2. It is shown that fat content of pullets is affected by the calcium content of the ration. The fat content was higher on a low calcium ration than on a high calcium ration.3. The CaO content of pullets was raised considerably by feeding a high calcium ration before laying. This CaO must have been stored in the bones, which contained between 97·2 and 98·7% of all the CaO in the body.4. The experiment suggests that pullets may use up to about one-quarter of their body calcium at the outset of laying for purposes of shell formation.5. The composition of the inorganic material of the skeleton of pullets may be modified by alterations in their mineral metabolism due to egg production on diets with and without a calcium carbonate supplement. The nature of these modifications and their relationship to calcium metabolism during laying is discussed.