Studies in Milk Secretion 



95 



this point on will be understood to 'be" for this expected record 

 at the standard age unless specifically mentioned to the contrary. 

 Thus the measure of the bull's transmitting ability (= daugh- 

 ter's milk production — dam's milk production) considers only 

 the expected milk productions. 



Variation of Corrected Registry of Merit Records. 



In all such investigations as the one in which we are en- 

 gaged it is desirable to know what error is likely to be involved 

 through the variation of milk production or butter- fat percent- 

 age due to chance. For the determination of this error the fre- 

 quency distribution of the expected milk production and butter- 

 fat percentage are necessary. These distributions are given in 

 table I and graphically shown in figure 24 and 25. 



TABLE 1. 



Frequency distributions of expected milk production and but- 

 ter-fat percentage of Jersey Registry of Merit cows, 

 mothers and daughters. 



Milk Production 



Frequency 



Butter-Fat 

 Percentage 



Frequency 















Daughter 



Dam 





Daughter 



Dam 



5499.5— 6499.5 



6 



1 



4.0995—4.2995 



5 



1 



6499.5— 7499.5 



71 



48 



4.2995—4.4995 



10 



2 



7499.5— 8499.5 



181 



153 



4.4995—4.6995 



31 



18 



8499.5— 9499.5 



214 



190 



4.6995—4.8995 



47 



30 



9499.5—10499.5 



176 



142 



4.8995—5.0995 



71 



50 



10499.5—11499.5 



149 



93 



5.0995—5.2995 



122 



83 



11499.5—12499.5 



97 



53 



5.2995—5.4995 



147 



105 



12499.5—13499.5 



57 



38 



5.4995—5.6995 



135 



120 



13499.5—14499.5 



30 



18 



5.6995—5.8995 



156 



110 









5.8995—6.0995 



125 



91 



14499.5—15499.5 



19 



7 



6.0995—6.2995 



101 



74 









6.2995—6.4995 



61 



53 



15499.5—16499.5 



10 



4 



6.4995—6.6995 



34 



37 









6.6995—6.8995 



20 



16 



16499.5—17499.5 



4 



9 



6.8995—7.0995 



13 



13 



17499.5—18499.5 



2 



2 



7.0995—7.2995 



2 



2 



18499.5—19499.5 



1 



2 



7.2995—7.4995 





1 



19499.5—20499.5 



2 



1 



7.4995—7.6995 



1 



1 



20499.5—21499.5 





1 









Total 



1019 



762 





1081 



810 



The Constants derived from Table I are shown in Table 



2. 



