No. 599] ADVANCED REGISTRY COWt 



681 



indicates here greater capacity for production of that 

 class, and as the capacity for production of the class in- 

 creases, so should the requirements increase. Therefore, 

 the curve of minimum requirement should be represented 

 as following the curve of plus deviation in character and 

 should be in a minus direction from the mean. 



In order to conform to these conditions some basis must 

 be established for calculating the minus points of the 

 curve, or, in other words, the minimum requirements for 

 each class. The average deviation of the whole popula- 

 tion seems to be the logical basis upon which the minimum 

 requirement should be based, for by its use the whole 

 curve may be lowered an amount corresponding to the 

 average deviation of the whole population below the mean 

 of the population. The average deviation from the mean 

 of the whole population is 69.8 pounds of milk. If all 

 classes are to be given the benefit of the average devia- 

 tion the calculation should start from the point at which 

 the means are at the maximum, which is about the six- 

 year class. Hence the six-year class is allowed as the 

 minimum requirement, the 69.8 pounds below the mean of 

 the class and the requirements of the other classes are 

 worked out from this point to conform, as said before, 

 to the maximum deviation curve. 



An inspection of these curves brings out the following 

 points : 



That the official requirements weight animals of an age 

 from 18 to 21 months too heavily. The curve indicates 

 that they are entitled to a reduction as great as for any 

 other age. For the purpose of discouraging such early 

 breeding, however, the requirements for this particular 

 class should be prohibitive and they are. 



That the production increases up to at least six years 

 of age instead of five, which the Holstein-Friesian Asso- 

 ciation requirements set as the maximum age production. 



That for this reason the 5- to 6-year-old animals and 

 possibly the 7- to 8-year classes have an advantage over 

 all other classes. , , 



That a comparatively small number of animals made 



