MASSACHUSETTS ANIMAL INDUSTRY 



Summary 



145 



The object of tlie work reported here has been to ascertain what benefit 

 may lie derived from adding steamed bone meal, with the animal matter 

 largely extracted, as a source of lime and phosphorus to the ration of dairy 

 cows. 



Tlie entire herd has been fed for four years on a ration low in mineral 

 matter, particularly in lime. One-half of the herd has had the deficiency 

 made good in theory by adding bone meal to the grain. 



The results in brief are as follows: 



1. The experiment has had no appreciable effect on the general condition 

 of the cows tiiat were mature when it commenced. This has been especially 

 true of the Holstein cows. The low mineral rations have adversely affected 

 some of the young cows, as evidenced by their unthrifty appearance and poor 

 appetite. The young Jerseys show this more than do the young Holsteins, 

 although there are exceptions in both breeds. For a long time there seemed 

 to be no difference in general condition between the "bone meal" and the "no 

 bone meal" group; but recently there has been some slight evidence to favor 

 the bone meal. 



2. The mature cows have not shown any significant changes in weight, Init 

 about half of the young cows are smaller than their dams were at the same 

 age. In this respect the evidence is about evenly divided, not favoring either 

 group. 



3. Milk production has been maintained well all through tlie experiment. 

 The evidence on this point favors slightly the "bone meal" cows. 



4. The composition of the milk has not been significantly affected. 



5. The reproductive function has been more seriously disturbed than any 

 other, considerable difficulty being experienced in getting the cows with calf. 

 The two groups have been quite similar in this respect. 



6. Each group has produced about the same proportion of strong, healthy 

 calves. The "no bone meal" group has had a somewhat higher proportion of 

 delicate calves, but this may have been due in part to breed cliaracteristics. 



Conclusions \xd Recommendations 



Our work has led us to the conclusion that while dairy stock, especially 

 growing heifers, must have an adequate supply of lime in their food in order 

 to attain maximum des'elo])ment and productive cajiacity, the advantage to be 

 gained from the practice of supplying lime in the form of steamed bone meal 

 seemed to lie very slight. 



While we have still much to learn on the subject of mineral feeding of 

 cows, the following recommendations are tentatively made: 



1. Supply lime and other minerals in feeds that are naturally rich in ash, 

 rather than by supplementing feeds low in ash with bone meal or other lime 

 salts. All the leguminous hays are high in lime, in addition to their very 

 desirable protein content. Alfalfa hay contains five times as much lime as 

 does timothy hay. There is as much lime in a ton of red clover hay as in 

 100 pounds of ordinary bone meal, and it is in what is probably a more de- 

 sirable form. It is in the choice of roughage that care must be used. The 

 ordinary grains and concentrates are characterized by relatively low lime and 



