I04 Bulletin 152. 



From the averages found in Table I it would seem that, as a 

 rule, the cow has nearly reached her full capacity for production 

 at the age of four years and that she does not gain as much in 

 the remaining year as is required by the equivalent record system. 

 On the other hand, a study of the cases given in Table VII 

 shows this S3'stem to be fairly accurate. It is without question 

 that the cows which have been tested several times are above the 

 average in power of production and for this reason they may be 

 more able to keep up the pace set for them than are the average 

 cows. 



GENERAL SUMMARY AND CONCLUSIONS. 



The largest total 3'ield of fat among two, three, four-year old, 

 or full aged cows, is, under every age, accompanied by the high- 

 est per cent of fat found among cows of that age. 



The smallest yield of fat for each age of animal is accompanied 

 in only one case by the lowest per cent of fat, and that among 

 the two-year olds. 



The largest yields of milk do not contain the lowest per cents 

 of fat nor do the smallest yields of milk contain the highest per 

 cents of fat. 



The stall fed cows average higher in total yield of milk and 

 fat and in per cent of fat than the cows at pasture. 



Equal quantities of the same kinds of food or similar quantities 

 of different kinds of food produce widel}^ varying amounts of 

 milk and butter in different animals. 



To produce the same or similar amounts of milk and butter 

 different animals require widely varying amounts of food. 



Cows, although of the same breed and raised in the same herd, 

 vary greatly in their power to make an economic use of food. 



The cost of production is greatest among two-year olds and 

 decreases gradually as the age increases up to four years, after 

 which there is little if any variation. 



Within a period of ninety days from calving there is but little 

 average variation in the per cent of fat among the different ages, 

 except that the average of all the tests made at thirty-one to 

 sixty days from calving is lower than for any other period. 



