ANIMAL PRODUCTION. 375 



Specific effects of rations on the development of swine, E. B. Fokbes, F. M. 

 Beexile, C. M. Fbitz, L. E. Morgan, and S. N. Rhue {OJiio Sta. Bui. 283 {1915), 

 pp. 111-152, figs. 12). — This is a continuation of work previously noted (E. S. 

 R., 22, p. 771), and of a preliminary metabolism study (E. S. R., 31, p. 2G8). 



Seven lots of five pigs each were used in a feeding and carcass-analysis ex- 

 periment in a study of tlie si^ecific effects of rations on the composition of the 

 growth produced. The rations were corn alone, and corn supplemented by soy 

 beans, wheat middlings, liuseed-oil meal, tankage, and skim milk. These rations 

 were fed in quantities such as contained the same amount of digestible nutri- 

 ment i^er unit of live weight of the pigs. The supplemented rations contained 

 the same proportions of protein to nonnitrogenous starch equivalent. The ex- 

 periment was in large measure a comparison of the capacities of pigs to grow 

 on equivalent amounts of protein from different sources. 



The capacity of digestible milk protein to cause proteid increase was shown 

 to be greater than that of digestible protein from the vegetable foods used and 

 from tankage. None of the supplements, used in proportions such that the 

 nutritive ratios of the rations are as 1 : 6.5, apparently furnished mineral matter 

 of the amounts and kinds requisite to maximum growth of bones. The rations 

 of com alone and of corn and soy beans produced the least bone, and that of 

 corn supplemented by tankage and by skim milk the most bone. 



The lot which received corn and linseed oil meal produced the largest per- 

 centage of flesh and leaf fat (together) and the smallest percentage of bone, 

 as related to the gross-dressed carcass, of any lot in the series. The lots 

 which received tankage and skim milk had the largest proportions of bone to 

 gross-dressed carcass, except for the lots which received corn alone, and corn 

 and soy beans, in which latter cases the higher proportion of bone to gross- 

 dressed carcass was due not to superior development of bone, but to inferior 

 nourishment of other tissues. The proportions of calcium, magnesium, and 

 phosphorus in the bones tended strongly to remain constant, but may be modi- 

 fied to a certain extent by the limitations of the food. The amounts of these 

 elements in the bone, however, are susceptible of much greater modification 

 through the composition of the food. The ash per gram of the bones and the 

 breaking strength of the bones were shown to vary together in the following 

 order of decreasing magnitude: Corn and skim milk; com and tankage; com 

 and linseed oil meal ; corn alone ; corn and wheat middlings ; and corn and soy 

 beans. The calcium and phosiihorus content of the skeleton was lower than in 

 the check lot (killed at the beginning of the experiment) in all lots except 

 those which received tankage and milk. The magnesium content of the skele- 

 tons of the pigs which received wheat middlings (a food very rich in magne- 

 sium) was higher than in the check lot. 



The ration of corn alone produced less moisture, protein, and ash, and more 

 fat in the flesh than did any of the supplemented rations, while the ration of 

 corn and skim milk produced the maximum of moisture and protein and the 

 minimum of fat in the flesh. There was marked variation in the content of 

 the flesh and blood in the mineral constituents, apparently as determined by 

 the food. Excluding the check lot, the sodium in the flesh varied between 

 0.0635 and 0.1036 per cent, potassium between 0.18SS and 0.2419 per cent, cal- 

 cium between 0.0217 and 0.0319 per cent, magnesium between 0.0146 and 0.0188 

 per cent, sulphur between 0.1289 and 0.1799 per cent, chlorin between 0.0353 

 and 0.0679 per cent, and phosphorus between 0.1227 and 0.1506 per cent. 

 There was also much variation in inorganic phosphorus and in lecithin, espe- 

 cially the latter (0.0147 to 0.0273 per cent). 



