FIFTY-THIRD ANNUAL CONVENTION 43 



must receive to enable them to assimilate and use the cal- 

 cium and phosphorus in their feeds. When calcium has 

 been added in such forms as calcium phosphate (the chief 

 mineral constituent in bones) or even by adding ground 

 limestone or marl, and the vitamin is also supplied good 

 results are secured. Howeevr, the simplest way of correct- 

 ing such a ration is to substitute alfalfa or clover hay for 

 half the straw in these rations. Entirely normal offspring 

 are then produced. 



The results of these nutrition trials have been corrobor- 

 ated by the experience of numerous farmers who have had 

 trouble with stock fed straw as the only roughage during 

 the winter feeding period. It, therefore, seems safe to con- 

 clude that straw is not safe to use continuously for a long 

 period as the only roughage for breeding stock, unless the 

 precaution is taken to add three to four ounces per head 

 daily of bone meal, finely ground limestone, or some other 

 material supplying lime. It is far preferable to use legume 

 hay as a part of the roughage for breeding cows, mares 

 and ewes. 



Mineral Requirements for Milk Production 



It has long been known that milk is rich in mineral 

 matter, especially in calcium and phosphorus. However, up 

 to a few years ago it was assumed that when dairy cows 

 were fed common, well-balanced rations containing plenty 

 of protein and a liberal amount of legume hay, there could 

 be no deficiency in either calcium or in phosphorus, for 

 legume hay is rich in calcium, and protein-rich feeds are in 

 general high in phosphorus. 



Surprising results were, howeyer, secured in extensive 

 experiments at the Ohio Experiment Station by Doctor 

 Forbes. In these trials high-producing cows have been fed 

 such excellent winter rations as alfalfa or clover hay and 

 corn silage for roughage, along with corn and such high pro- 

 tein concentrates in addition as wheat bran, cottonseed 

 meal, linseed meal, dried distillers' grain, or gluten feed. 



On these rations, which have always been considered 

 ideal for dairy cows, in most instances the animals lost cal- 

 cium, phosphorus, and also magnesium from their bodies. 



