MINERAL NUTRITION 159 



2. The mineral supplement had little, if anj-, effect on the growth of the j'oung 

 cows and heifers. 



3. The low ash ration apparently had no adverse effect on milk production, 

 and the mineral supplement apparently had no favorable effect. 



4. The composition of the milk was not significantly affected. 



5. Reproductive troubles were not serious in either group, but the cows receiv- 

 ing the mineral supplement were a little nearer normal and produced on the whole 

 somewhat better calves than did those that did not receive it. 



6. It must be emphasized that none of the differences between the groups was 

 sufficiently striking to warrant as a general recommendation the use of the dical- 

 cium phosphate-calcium carbonate mixture. 



Where cows are average producers (5000-8000 pounds), and where they are 

 fed normally on good quality roughage the need of a mineral supplement is not 

 indicated. For heavy producers (10,000 pounds and upwards) it is probably 

 good insurance to supply supplemental lime and phosphorus, but the efficacy 

 of such a practice is by no means well established. 



It has been nothing short of amazing to note the persistency with which the 

 cows devoted to this study have maintained their milk production and for the 

 most part their own well-being on low ash rations over a period of years. If these 

 cows which average over 9000 pounds of milk yearly (several of them being 11,000 

 to 12,000 pound cows) can make such a showing on abnormal rations, it seems 

 reasonable to infer that the average New England cow on good quality roughage 

 must have a considerable margin of safety as far as minerals are concerned. It 

 seems probable that the mineral problem is a regional or local one. If soils on 

 which roughages are grown are so deficient in lime or phosphorus as to produce 

 feeds low in these ingredients, then the addition of a mineral supplement may 

 prove helpful. It is not believed that such conditions with respect to calcium 

 prevail in New England, while possible deficiencies of phosphorus in our roughages 

 are made good bj" the liberal grain feeding practiced in this section of the country. 



Part II. MINERAL MATTER IN CATTLE FEEDS 



In order to ascertain the mineral content of the ordinary roughages grown by 

 farmers in Massachusetts, numerous samples of hay and corn silage — the two 

 staple coarse feeds — were collected with the aid of the county agents from different 

 sections of the State, and analj^zed for the most important mineral constituents. 

 It was surprising how few analyses were on record, especially of the calcium con- 

 tent of cattle feeds. In the following pages are given the results, together with 

 such brief comments as seem necessary. 



Mineral Matter in Massachusetts Roughages^ 



Sixty-eight samples, including thirty-two of hay, twenty-four of corn silage and 

 twelve miscellaneous roughages were collected and analyzed. They were obtained 

 from thirty-three farms in twenty-nine towns, located in eleven counties. 



The results, in order to be comparable, are expressed in the case of hay on a 10 

 per cent water basis and in the case of silage on a 78 per cent water basis, and also 

 on an elemental basis; that is, as the elements, calcium (Ca) and phosphorus (P) 

 instead of as the oxides CaO and P2O5, etc. In Table 1 they are arranged on the 

 basis of location in the State, beginning with Barnstable County in the southeast 

 and continuing to Berkshire County in the west. 



• All of the analytical work was done by H. D. Haskins and L. S. Walker of the Control Service. 

 The methods followed were those of the Association of Official Agricultural Chemists. 



