FIFTIETH ANNUAL CONVENTION 77 



house, doling out these minerals so that the life processes 

 of the body may continue normally for a time. Under such 

 conditions the calcium and phosphorus in the muscular 

 tissues and other vital tissues of the body remain practically 

 as high as in animals liberally supplied with these minerals. 

 In a trial at the Wisconsin Experiment Station by Hart, Mc- 

 Collum, and Humphrey a cow fed a ration deficient in cal- 

 cium during 110 days gave off 5.5 pounds more calcium in 

 milk and excrement than was in the feed. This was about 

 one-fourth of all the calcium in her body, including the 

 skeleton, at the beginning of the trial. 



Such withdrawal of mineral matter from the skeleton 

 produces porosity and brittleness of bone. In certain local- 

 ities where thq hay and other roughages are especially low 

 in calcium and phosphorus, farm animals are( so affected by 

 the lack of these mineral substances that their bones are 

 broken easily and in seemingly inexplicable ways. Often 

 this brittleness of bone is noticeable only in years when the 

 normal absorption of calcium and phosphorus by the roots 

 of plants is hindered by drought. Of grown animals, those 

 carrying their young are most apt to suffer from the lack 

 of these substances, since considerable amounts are deposit- 

 ed in the fetus. Growing animals whose bones are rapidly 

 increasing in size suffer from a lack of calcium or phos- 

 phorus sooner than grown animals. 



Fortunately, roughage from the legumes, such as clo- 

 ver and alfalfa hay, is especially rich in calcium and is also 

 quite high in phosphorus. Previously the high value of 

 these roughages in stock feeding has been attributed pri- 

 marily to their richness in protein. Experiments carried 

 on continuously since 1908 at the Wisconsin Experiment Sta- 

 tion by Hart, Steenbock, and Humphrey have shown clearly 

 that the beneficial effects of leguminous roughages are also 

 due to their richness in lime. Dry cows fed oat or wheat 

 straw, with grain and grain by-products added to make a 

 ration balanced according to the feeding standards, have 

 usually aborted or produced dead or weak offspring. When 

 calcium has been added to the ration in such forms as cal- 

 cium phosphate or wood ashes, the results have been great- 



