98 Feeds and Feeding. 



several trials we may conclude that mature ruminants can be main- 

 tained for considerable periods, if not indefinitely, on a limited 

 amount of ground grain with no roughage, and if liberally sup- 

 plied with grain only, they may make fair gains in weight. With 

 young ruminants Nature seems less yielding. Apparently calves 

 cannot be brought to maturity upon grain and skim milk, either 

 separately or combined, as their sole feed, but they must have some 

 coarse forage, without which rumination is impossible. 



121. McCollum's experiment. At the Wisconsin Station 1 McCol- 

 lum placed a 23-lb. sow pig in a dry lot with shelter, and fed it 

 from May to July of the following year, at first on whole milk and 

 skim milk, and later on skim milk alone. The sow remained in 

 excellent condition, and at about 1 year of age, when weighing 

 406 Ibs., gave birth to 8 living pigs averaging 2.3 Ibs. each, and 2 

 dead ones, all normal. Before winter, the pigs made an average 

 daily gain of 0.39 Ib. each, reaching an average weight of 18.6 Ibs. 

 in 6 weeks. 



This shows that milk alone will support the pig, and indicates 

 that the failure of Davenport to maintain calves on skim milk and 

 grain was probably due to the physiological requirement of her- 

 bivora for coarse food to fill the first three stomachs in order that 

 they may develop normally. (32) The pig has no such peculiarity 

 in the structure of its digestive tract, and hence no physiological 

 disturbances result from taking liquid food alone in the form of 

 milk. 



122. Inorganic phosphorus for pigs. Hart, McCollum, and Fuller 

 of the Wisconsin Station 2 conducted experiments to determine 

 whether animals can assimilate inorganic phosphorus compounds 

 a point in dispute among scientists. 



Wheat bran contains about 6 per ct. of phytin, an organic com- 

 pound of lime, phosphorus, magnesia, and potash. By washing a 

 quantity of bran with warm water the phytin was dissolved and 

 removed. After drying, the material was mixed with wheat gluten 

 and rice, which are both extremely poor in mineral matter. To 

 this mixture was added sugar to give palatability, also a quantity 

 of sodium chlorid, magnesium chlorid, and potassium sulfate suffi- 

 cient to replace the amount of these salts washed from the bran. 

 The combination formed a basal ration poor in phosphorus. 



1 Unpublished data. 2 Research Bui. 1. 



