The influence of calcium and phosphorus in the feed on the milk yield of dairy cows /

Abstract

12 Description of experiments, protocols, and tables 13 Effects, on milk yield, of liberal feeding during dry period 13 Effects, on milk yield, of feeding phosphate with alternated rations during dry period 14 Page. Description of experiments, protocols, and tables --Continued. Rations given animals before calving 18 Condensed history of experimental animals 20 Effects of phosphate feeding ou body weight 23 Quantitative results 24 Grain mixtures used in experiments 25 Account of unsuccessful and incomplete experiments 26 Literature cited 27 DAIRY PRACTICES AT THE GOVERNMENT FARM AT BELTSVILLE. 1Opportunities for observing the effects of the feed on milk secretion 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 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 2 BULLETIN 945, U. S. DEPARTMENT OF AGRICULTURE. meal, linseed meal, alfalfa and other legume hays, and corn silag® and stover. Most of the cows have had a little pasture in the summer, but not enough to make up any considerable proportion of the total amount of feed eaten in the year.The aim has been to feed the cows as much protein as is required by the most liberal of the American feeding standards, to keep them in good condition, to have them calve once a year, and to have them dry each year for 6 to 8 weeks before calving. It has generally happened in practice that the cows were fed a little less liberally than is demanded by the Savage and Eckles standards (9) 2 for the first two or three months after calving, and a little more liberally later.When they were dry they were usually fed 4 pounds of grain mixture B, 3 4 pounds of legume hay, and as much silage as they would clean up. When the hay was alfalfa and the amount of silage eaten daily 30 pounds, which was the most usual state of things, this ration provided 1.29 pounds of digestible crude protein and 10.29 pounds of total digestible nutriment daily. After subtracting the maintenance requirement for a 1,000-pound cow, this would allow 0.59 pound protein and 2.37 pounds total nutriment daily for the growth of the unborn calf, which, according to the results obtained by Eckles (3), ought to be sufficient.We have recently calculated the protein and total nutriment in the yearly rations of a number o...