164 Essay on the Interpretation of Milk Records. 



Lactation periods other than " normal " were dealt with in 

 a similar manner and gave results summarised in the following 

 table : — 



M = Mean. 



cf = Standard deviation. V = Variation coefficient, r = Correlation with totah. 

 Totals in gallons. Remainder in quarts. 



Several points are brought out by this table : — 



(i.) That whatever the length of lactation period, the 

 average, revised maximum and maximum are very little 

 influenced by it, and are all definitely coiTclated, in all cases, 

 with the total production of the cow. 



(ii.) That as we pass from averages to revised maxima to 

 maxima, the variability shows a tendency to decrease ; that as 

 a rule the least variation is found in the maxima. 



(iii.) That correlation with totals decreases in the same 

 direction. This at first sight appears somewhat conti'adictory 

 to (ii.), but since totals represent the estimate of yield given by 



