148 Journal of Agricultural Research vol. xx, no. 2 



milk functions as base because the lactic acid is oxidized to carbonic acid, 

 which is thrown off by the lungs, leaving the basic residue of mineral 

 salts. Dried skim milk or dried buttermilk is therefore quite base in 

 function. Dried blood, on account of its magnesium, calcium, and sodium 

 content, is moderately base. 



In these studies there have been arranged 1 1 feed mixtures for acid- 

 base studies. The first 7 are North Carolina Experiment Station for- 

 mulae and the last 4 are those of Prof. Rice. The mixtures that contain 

 considerable amounts of either dried milk, meat and bone meal, or digester 

 tankage are quite base. The mixture containing soybean meal is approxi- 

 mately as much base as the grain mixture is acid, so that equal amounts 

 would approximately balance so far as acid-base content is concerned. 

 The peanut meal mixture is slightly below the soybean meal mixture, 

 and the blood meal comes slightly below the peanut meal. 



We note from Table III that the grain mixture contains 12 per cent 

 protein calories and the ground feed mixtures contain from 19 per 

 cent in the mixture containing peanut meal in which peanut meal not 

 fat-extracted to 31 per cent in the ration in which blood meal was used. 

 We note by a study of Table IV, which gives the total intake of each 

 mixture for each period, that the final percentage of protein calories 

 runs from 13 to 22. For comparison with rations for human beings 

 we may again refer to the study of army rations during the late World 

 War, in which the percentage of protein calories ran from 10 to 18. 

 Dr. Osborne 1 found that 12.5 per cent protein calories produced maxi- 

 mum growth in rats. The indications are that the kinds as well as the 

 quantities of proteins are essential factors. While the kinds of amino 

 acids and vitamins are important factors in addition to kinds and quan- 

 tities of minerals, there is a possibility that there are other factors un- 

 discovered which have a profound bearing on growth, egg production, 

 and the preparing of pullets, by aiding the storing up of potential energy, 

 for early and heavy egg production. Data which will be published later 

 show that pullets grown on range or in confinement without animal food 

 of any kind, though the protein calories were above those indicated in 

 comparison rations, 1 were not prepared for early heavy egg production 

 and did not show high egg yields until animal food of some kind had 

 been added. In this instance this was the soybean meal and peanut- 

 meal lots. In the second and third periods the balances of intake was 

 acid. 



Further studies are being made to determine whether acid feeds will 

 in any way interfere with either growth or egg production. In these 

 studies rations 5 and 6 can be made base by the addition of ground 

 limestone or gound oyster shell. The amounts to be added would 

 depend upon the proportions in which the mash and grain were fed. 



1 Osborne, Thomas B., and Mendel, Lafayette B. a quantitative comparison of casein, lactal- 

 bumin, and edestin for GROWTH or MAINTENANCE. In Jour. Biol. Chem., v. 36, no. 1, p. 9. 1916. 



