The Calcium-Phosphorus Ratio in the Nutrition of Growing Chicks

Abstract

Published with the permission of the Director of the Wisconsin Agricultural Experiment Station.The Ca-P ratio in cows milk as well as the milk of other mammals is approximately 1 :.65. It has been found by Simmonds 1 that the optimum amounts of calcium and phosphorus for the rat are approximately .65 gram of calcium and .40 gram of phosphorus per 100 grams of food mixture. These proportions give a Ca-P ratio of 1 :.62, a ratio quite similar to that found in milk. Because of the ideal character of milk as a food for the young, and because of the results secured by Simmonds, this ratio has been emphasized as the most suitable one in ration construction for the rat and possibly other mammals.In the hen's egg-exclusive of shell-the Ca-P ratio is very different from that of milk and shows a preponderance of phosphorus over calcium. The ratio is 1:2.77. These figures are based on analyses of the combined white and yolk of the egg, but do not include the shell. It was of interest to us to determine the change in the Ca-P ratio during the incubation of the egg as a means of throwing light on the possible variation that may exist in such ratios in normal living tissues.For this purpose eggs were selected from hens of identical feeding. The ration of the hens was a complex grain mixture fed as mash and scratch, supplemented with skim milk and fortified with cod liver oil and winter sunshine. Before placing the eggs in the incubator, five of them were taken for an initial determination of the calcium and phosphorus content of the combined white and yolk. For this determination the white and yolk were mixed and dried, the membrane lining the shell being included in the analyzed material. A sufficient number of the eggs was 296 at Northern Arizona University on June 7, 2015 http://ps.oxfordjournals.org/ Downloaded from POULTRY SCIENCE

The Calcium and Phosphorus Contents of Chickens of Various Ages

“…The day-old chicks contained approximately 0.14 grams calcium and 0.11 grams phosphorus. These values are in harmony with those obtained by Hart, Scott, Kline and Halpin (1930), for the contents of eggs incubated for 20 days and with the calcium contents of day-old chicks as found by Mitchell, Card and Hamilton (1931). There is also good general agreement with the results of Ackerson,Blish & Mussehl (193S) for day-old chicks.…”

Perosis, or Deforming Leg Weakness, in the Chicken

“…Experiment 6.-The next experiment was conducted along similar lines for the purpose of studying the effect of adding various amounts of rice bran to the original diet after its calcium-phosphorus ratio had been changed from 1.54:1 to 3.24:1 by substituting calcium carbonate for the bone meal. * The results indicated that 6 * Recent experimental work [Bethke, Kennard, Kick, and Zinzalian (1929) and Hart, Scott, Kline, and Halpin (1930)] has indicated that the optimum calcium-phosphorus ratio of the chick is between 2:1 and 4:1. Wilgus (1931), claims that it is between 1:1 and 2:2:1 and that "A ratio of 2 :S :1 is borderline while 3:3:1 is disastrous."…”

Cereals and Rickets

“…Massengale (1929) reported that a rachitogenic diet low in Ca and high in P produced a noticeable leg weakness at an earlier age than a diet low in P and high in Ca. Hart, Scott, Kline, and Halpin (1930) observed that with a minimum amount of vitamin D the best calcification and growth was obtained at a Ca/P ratio of 4:1 to 3.3:1 with 2.49 percent to 2.71 percent Ca and 0.66 percent to 0.83 percent P in the ration. Wilgus (1931) advanced evidence to show that when an optimum supply of the antirachitic factor is provided, the Ca/P ratio * Published with the permission of the Director of the Wisconsin Agricultural Experiment Station.…”