142 



Maine Agricultural Experiment Station. 1920. 



The conclusion appears justified that the frequency distrib- 

 utions for butter-fat percentage in cow's milk are slightly asym- 

 metrical and that this skewness is in the plus direction. 



The Correlation of Jersey 8 Months Butter-Fat Per Cent 

 With Age of the Cow at Commencement of Test. 



Increase in age of the cow from the time she is a heifer to 

 the time she is at her maximum productivity at J years has been 

 shown to bring about a logarithmic increase in the quantity of 

 eight months milk produced by that cow. The effect of increas- 

 ing the age of the cow on the quality is of equal interest to the 

 student of the physiological behavior of the mammary gland. 

 The data for this comparison in the herd of pure bred Jersey 

 cows with which this study deals are shown in Table 3. 



TABLE 3. 



Correlation Surface for Butter-Fat Percentage and Age at Test 

 For Jersey Cattle. (Lactation Period 8 Months). 





















BUTTER-FAT 



% 



























in 

 co 























































1 



in 







in 







in 



CD 



10 







in 







w 



CD 



in 



CD 



10 





m 



CD 



in 







in 







i 



"3 



4J 





10 



CO 



00 



OS 





CSJ 



""! 



10 



1- 



Sj 







r-i 



CO 



•** 



O 



j~ 



c-. 







CI 



GO 



in 



CO 



00 



OS 



O 





eo 



eo 



CO 



CO 



■* 



■»* 



** 



■<* 



■* 



■* 



ie> 



in 



10 



in 



in 



in 



id 



CO 



CO 



co* 



CO 



CD 



cd 



CO 



EH 



1:6— 2:0 















1 



3 



2 



3 



3 



3 



7 



7 



3 



4 



1 



1 















38- 



2:0 





1 









4 



11 



12 



13, 24 



35 37 



42 



25 



10 



13 



10 



5 



5 



2 







1 





250 



2:6 













1 



3 



13 5 7 7 



6 



3 



2 





3 



3 







1 



1 







46 



3:0 













3 



6 



5! 12 11' 18 34 



15 



19 



16 



6 



8 



1 



1 



1 





1 



1 





158 



3:6 













1 



3 



9 4 13 13, 10 



7 



6 



7 



3 



3 



1 



2 



2 



2 



1 







87 



4:0 













1 



2 



5 12 18; 15 1 15 



18 



13 



13 



9 



4 



3 



2 



1 







1 





132 



4:6 













1 



2 



6 



9 14 12 15 



11 8 



8 



3 



6 





1 





2 









98 



5:0 











1 







7 



11! 9| 18 j 13 



14 14 



10 



6 



3 











1 







107 



6:6 











2 





4 



9 



5 15 13! 21 



14 i 13 



7 



4 



5 



1 





1 



1 









115 



6:0 













4 



3 



6 



6 12 



10 13 



9 13 



2 



5 



3 



1 



1 



1 



1 









90 



6:6 









1 



1 



2 



3 



6 



9 1 11 



18 13 141 8 



8 



3 



2 



3 















102' 



7:0 -m 











1 





4 



3 



11 



10 



61 12| 16 



5 



5 



2 



3 



2 











1 





81 



7:6 S 









2 





2 



3 



6 



6 



12 



13 16 12 



11 



1 





3 



3 















90 



8:0 EH 







1 







' 1 



5 



4 



7 



3 



11! 10 



10 



10 



3 



1 



4 

















70 



8:6 *> 













2 



3 



6 



1 



7 



6 11 



8 



8 



1 



2 



1 



1 















57 



9:0 * 







1 



1 





2 



1 



3 



1 



6 



3 4 



11 



5 



2 



6 



2 

















48 



9:6 ?„ 











1 



3 



1 



3 



4 



3 



4 3 



3 



8 2 



1 



1 

















37 



10:0 £ 

 10:6 











1 





1 



1 



4 



4 



21 4 



3 6 



l. 1 



1 







1 













29 













1 



1 



3 



1 



3 



1 3 



4 



2 





1 



1 

















21 



11:0 













1 









1 



3 



4 



5 



1 



1 



1 





1 















18 



11:6 













1 







1 



2 





6 





1 



1 





















12 



12:0 









2 











1 



1 



1 



1 







1 







1 















8 



12:6 













1 





1 



2 





2 





1 



1 























8 



13:0 











1 



1 







1 





1 



2 



























6 



13:6 



























1 



1 























2 



14:0 























1 



1 



























2 



14:6 





























1 























1 



15:0 





















































15:6—16:0 





















































Total 



1 



2 



6 8 



32 



57 



99,126 187 216 



258 



231 189 104 



71 



63 



27 



13 



8 



7 



4 



4 





1713 



