CALCIUM AND PHOSPHORUS IN THE FEED OF DAIEY COWS. 27 



aborted after a period on the phosphate feeding might give more 

 milk than they ever had before. We have no knowledge of the 

 amount of her milk yield after the abortion. 



Besides the cases so far reported, there are only seven animals 

 which received any sodium phosphate at all. One of these received 

 small daily doses (6.9 grams phosphorus as sodium phosphate) from 

 the time she was born to when she dropped her first calf. She 

 aborted with this calf, and gave a rather small quantity of milk sub- 

 sequently. On account of the abortion and of the fact that the doses 

 of phosphate were small, we do not think that this experiment throws 

 any light at all on the question of the effects of phosphate feeding on 

 the subsequent milk yield. . 



The six other animals received basal rations alone and then the 

 same rations with phosphate added for short alternated periods, the 

 main purpose of the experiments being to determine the effects of 

 feeding phosphate on the concentration of phosphorus in the blood. 

 Three of these happened to abort after periods of a week or more on 

 rations without phosphate. They gave about the quantities of milk 

 which would have been expected on the supposition that they had 

 never had phosphate. 



The other three dropped their calves while on the phosphate feed- 

 ing. Two of them aborted after 7 and 10 days of phosphate feeding 

 respectively. Both gave more milk than they ever had before, and 

 decidedly more than would have been expected on the supposition that 

 they had never had phosphate. The third was a heifer carrying her 

 first calf. She calved normally at term after 26 days of phosphate 

 feeding and gave much more milk than the general average for the 

 herd with their first calves. These last three results suggest that even 

 a short period of phosphate feeding may have a markedly favorable 

 effect on milk yield if it occurs during the few days immediately 

 before calving, during which the udder is rapidly enlarging in prep- 

 aration for the coming lactation period. 



LITERATURE CITED. 



(1) Bek.tkam, J. 1878. Ueber die Ausscheidung der Phosphorsaure bei den 



Pflanzenfressern. In Ztschr. Biol., v. 14, pt. 3, p. 335-382. 



(2) Eckles, C. H. and Palmes, L. S. 1916. The influence of the plane of 



nutrition of the cow upon the composition and properties of milk and 

 butterfat. Mo. Agr. Exp. Sta. Research bul. 25. 



(3) Eckles, C. H. 1916. The nutrients required to develop the bovine fetus. 



Mo. Agr. Exp. Sta. Research bul. 26. 



(4) Forbes, E. B., with collaborators. 1914. The metabolism of organic and 



inorganic compounds of phosphorus. Ohio Agr. Exp. Sta., Tech. ser. 

 bul. 6, p. 66. 



(5) Forbes, E. B., with collaborators. 1916-1918. The mineral metabolism of 



the milch cow. Ohio Agr. Exp. Sta. Buls. 295, 308, and 330. 



