266 Agricultural Chemistry. 



maximum efficiency in milk production are not possible. Where, 

 however, alfalfa and clover make the hay, and peas and oats are 

 rrown, a protein supply consistent with efficiency can be pro- 

 duced. 



There is the additional fact that the production of milk de- 

 mands a plentiful ash supply to the animal. Thirty pounds of 

 milk will contain nearly an ounce of lime and the same quantity 

 of phosphoric acid. Besides the quantities secreted in the milk, 

 there is apparently a waste from cell activity, which in the case 

 of a dairy cow yielding 30 pounds of milk, was found to be nearly 

 equal to the quantity secreted in the milk. In an experiment at 

 the Wisconsin Station, where a ration was made up of oat straw, 

 rice, wheat bran and wheat gluten, a cow continued to give a milk 

 of constant composition in respect to lime content, as well as all 

 other constituents; yet the amount of lime supplied the animal, 

 for a period of over 100 days, had been deficient. To maintain a 

 normal composition of the milk, the animal had withdrawn lime 

 from her skeleton, a remarkable transmigration of material. The 

 health of the animal was apparently unimpaired, but it is self- 

 evident that ultimately the milk flow must have ceased or the 

 animal would have collapsed. While the ration used was unusual, 

 the experiment, however, emphasizes the necessity of a liberal 

 supply of ash material for the dairy cow. The legume seeds and 

 cereal grains are low in lime, but are fairly rich in phosphorus. 

 Wheat bran is relatively poor in lime, but rich in phosphorus. 

 Ten pounds of bran will supply about one-fourth of an ounce of 

 lime, but nearly one-third of a pound of phosphoric acid. The 

 hays from the true grasses are fairly wejl supplied with lime, 

 but the legume hays, as clover and alfalfa, are particularly rich 

 in this material, and should, for this reason, form a part of the 

 nit ion of the dairy cow. 



It would appear, then, that in most rations recognized by 

 dairymen as efficient for milk production, phosphoric acid and 

 lime will be plentifully supplied, especially where bran and the 

 legume hays constitute a part of the ration. But should straws 

 form the niuLrlui'jr. th<> supply of lime may become deficient. 



