Essay on the Interpretation of Milk Records. 1G7 



on the other hand these influences are generally favourable it 

 will merely mean that this ideal environment occurs more 

 frequently. The maximum will be as before, but the average 

 will be increased. One cannot help feeling that this is, in the 

 main, the explanation of the fact that in the present investiga- 

 tion the variation coefficient of the " maximum " has in every 

 case come out lower than that of the " average." 



2. The second class of error is that to which any one 

 weighing, whether daily or weekly, is exposed, such as late 

 milking, early milking previous afternoon, extra food, wind, 

 clerical mistakes, &c.; in short, all the usual disadvantages of a 

 single sampling. These would have full effect on the maximum, 

 but might be considered negligible on an eight-weeks' average. 



It was when faced with these two methods, each with its 

 concomitant error, that the writer endeavoured to avoid both 

 by the use of the revised maximum, the variation constants of 

 which have been inserted in most of the foregoing tables.^ 



Whether this use is justified remains for further work and 

 maturer opinion to decide. At the present time, in the absence 

 of both, it is being used for attacking the more practical 

 problems of selection and breeding. 



(b). Circumstances affecting the Revised Maxhnum. 



"With regard to this section of the subject, the number of 

 records so far extracted is perhaps not large enough to justify 

 any exact figures, but the results so far obtained will be given, 

 with the proviso that slight modifications may be found 

 necessary with further work. 



Influence of Age. — The following diagram gives the mean 

 revised maxima of 110 cows with their first six calves. 



Fio. 5. — Mean R.M. with successive Calves given by 110 Cows. 



16 4- 



^^^ cows on^) 



1st calf. 2nd calf. 3rd calf. 4th calf. 5th calf. 6th calf. 7th calf. 



* The revised maximum has further the very great practical advantage over 

 the average that it requires no calculation. 



