MASSACHUSETTS ANIMAL INDUSTRY j^j 



The mineral content of the entire ration was still further lessened by sub- 

 stituting for a portion of the hay, during certain periods of the experiment, 

 such mineral-poor materials as chopped oat straw, starch, or apple pomace. 



The whole herd has been fed as described above for four years, and in addi- 

 tion, one-half of the herd, known as the "bone meal" group, has received 

 supplemental calcium and phosphorus in the form of steamed bone meal 

 specially prepared for animal feeding. The bone meal was thoroughly mixed 

 with the grain before feeding and the amount for each cow has varied with 

 her weight and the amount of milk she gives, from three to eight ounces daily, 

 the aim being to supply approximately a 60 per cent excess over the the- 

 oretical requirements of each cow. This excess is provided as a safeguard; 

 for, although little is known about how completely mineral matter in the form 

 of ground bone is utili/.ed by the dairy cow, it is safe to assume that it is only 

 partially digested and made available. 



Results oi the Experiment 



General Condition and Weight of the Cows. 



The condition of the animals has been carefully noted by means of ob.serva- 

 lions made and recorded from month to month. At no time has it been pos- 

 sible to note any marked diflFerence in the mature cows. Irrespective of the 

 group in which they belong they have maintained themselves well. This has 

 been especially true of the Holstein cows. 



Among the young cows and heifers tiie effects of the low mineral ration 

 have been much more apparent. Several of them are considerably under- 

 sized for their age, and present a general unthrifty appearance. Recently 

 some of them have had very poor appetites, refusing at times both hay and 

 grain. The young Jerseys seem to have been ])arricularly susceptible, and 

 while some of the Holsteins have also been affected they iiave stood uj) under 

 the low mineral feeding better than the Jerseys. As with the aged cows the 

 effects noted have been irrespective of whether they received bone meal or 

 not, although recently there has been some evidence to favor the bone meal. 



All of the cows that were mature at tlie commencement of the experiment 

 have maintained tiieir weights well, there being no significant variation from 

 year to year in either group. 



Gkowth of Heifers 



Study of the growth records of the young stock in comparison with those 

 of their dams shows that of twelve individuals, six are as large as their dams 

 were at the same age and six are smaller than the dams were. These two 

 groups are composed according to breed as follows: 



Large as da/m Smaller than dam, 



Holstein — i Holstein — 8 



Jersey — 2 .Jersey — 3 



According to grouping in the experiment Lhey are divided thus: 



