UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 945 



Contribution from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



j&y°^(„ 



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. B. Woodward, 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 on 



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, aDd carried out this part of the work 

 with unusual care and accuracy. 

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