UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 945 
Contribution from the Bureau of Animal Industry 
JOHN R. MOHLER, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
May 27, 1921 
THE INFLUENCE OF CALCIUM AND PHOSPHORUS 
IN THE FEED ON THE MILK YIELD OF DAIRY 
COWS. 
By Edwaed B. Meigs, Physiologist, and T. E. Woodwabd, Dairy Husbandman, 
Dairy Division. 
CONTENTS. 
Page. 
Dairy practices at the Government 
farm at Beltsville 1 
Standard rations insufficient for op- 
timum milk yield 3 
Nature of the deficiency in the routine 
rations fed at Beltsville 5 
Discussion of results 9 
Summary 12 
Description of experiments, proto- 
cols, and tables 13 
Effects, on milk yield, of liberal 
feeding during dry period 13 
Effects, on milk yield, of feeding 
phosphate with alternated ra- 
tions during dry period 14 
Page. 
Description of experiments, proto- 
cols, and tables — -Continued. 
Rations given animals before 
calving 18 
Condensed history of experi- 
mental animals 20 
Effects of phosphate feeding ou 
body weight 23 
Quantitative results 24 
Grain mixtures used in experi- 
ments 25 
Account of unsuccessful and in- 
complete experiments 26 
Literature cited 27 
DAIRY PRACTICES AT THE GOVERNMENT FARM AT BELTSVILLE. 1 
Opportunities for observing the effects of the feed on milk secre- 
tion have been rather favorable on the dairy experimental farm at 
Beltsville, Md., where the authors are stationed. Since 1912 a herd 
of from 50 to 100 cows, some of which are purebred Guernseys, 
Jerseys, or Holsteins, and some grades, has been maintained here. 
Daily records have been kept of the milk yields throughout, and 
yearly records of the feed consumed up to 1918. Since 1918 monthly 
or daily records of the rations have been kept. The fat in the milk of 
each cow has been determined once a month, and from the results so 
obtained the monthly and yearly yields of fat have been calculated. 
The feeds chiefly used have been corn meal, wheat bran, cottonseed 
1 The authors wish to acknowledge the valuable services of H. J. Nedrow, H. T. 
Converse, and W. E. Benscoter. Messrs. Nedrow and Converse were the herdsmen at the 
Beltsville farm during the period when the experiments were carried out, and they 
supervised the feeding and care of the experimental animals. Mr. Benscoter was 
responsible for the feeding in a number of cases, and carried out this part of the work 
with unusual care and accuracy. 
27763°— 21 1 
