Animal Husbandry Investigations in 1919. 



263 



TABLE 3. ' "' 



Actual Milk Production of Two Year Old Cozvs (8 Months of 

 Lactation) and the Expected . Five Lactation Yield. 



Actual Milk Production 



Expected Five Lactation Yield 



1375 to 1625 



Mil:; 



1625 to 1875 



15221 



1875 to 2125 



16300 



2125 to 2375 



17378 



2375 to 2625 



18457 



2625 to 2875 



19535 



2875 to 3125 



20614 



3125 to 3375 



21692 



3375 to 3625 



22770 



3625 to 3875 



23849 



3875 to 4125 



24927 



4125 to 4375 



26006 



4375 to 4625 

 4625 to 4875 

 4875 to 5125 

 5125 to 5375 

 5375 to 5625 

 5625 to 5875 

 5875 to 6125 

 6125 to 6375 

 6375 to 6625 



27084 

 28163 

 29241 

 30320 

 31398 

 32477 

 33555- 

 34634 

 35712 



Similar information to that given above for milk production 

 has been analyzed and the results made available for the per- 

 centage of butter-fat. The records for analyses were the same 

 as those used for the milk yield just given. The relation which 

 exists between the average butter-fat percentage of the first five 

 lactations and the butter-fat percentage of the individual lacta- 

 tions is given in the table 4. This table has the same arrange- 

 ment as table 3. 



TABLE 4. 



Correlation Coefficients for the Butter-fat Percentage of a Lac- 

 tation at a Given Age and the Butter-fat Percentage for 

 the First Five Lactations of a Cozv's Life. 



Age when Lactation 

 Commenced 



2 years to 3 years 



3 years to 4 years 



4 years to 5 years 



5 years to 6 years 



6 years to 7 years 

 Five lactation but- 

 ter-fat percentage 



Mean Milk Yield lor 

 that Lactation 



5.25±.04 

 5.23+.04 

 5.29+.04 

 5.23+.03 

 5.18-K03 

 5.22+.03. 



Correlation Coeffi- 

 cient for Individual 

 Standard Deviation Lactation Records 

 of Milk Yield and the first five 

 !Lactation's Total 

 ; Yield 



0.49+.03 

 .49+.03 

 .50-K03 

 .46+.02 

 .43+.02 

 .40+.02 



+0.797±.026 

 .836-K022 

 .862+.018 

 .857-K019 

 .784+. 028 



