214 



Maine Agricultural Experiment Station. 1918. 



glands goes the variations of this milk, fall in well with the 

 secretory hypothesis to account for these solids. 



Cattle Judging as a Means of Selecting Cows for the Herd 



The importance of this question would be hard to over- 

 estimate as a' knowledge of the kind of conformation that goes 

 with a high milk producing cow would be of material aid in the 

 buying of cows for the herd and also for the selection of young 

 heifers to be kept for further use. As indicated by a previous 

 report the Biological Laboratory has a project on foot to accu- 

 mulate an exact body of data to determine the relative value of 

 the points used in judging dairy cattle for milk production. This 

 work: is progressing favorably. In the meantime use has been 

 made of data found in volume I of the Registry of Merit pub- 

 lished by the American Jersey Cattle Club. These data give 

 the milk, butter-fat and butter-fat per cent together with the 

 scores ofsome 6^2 milk cows at different ages. The resulting 

 correlation of milk production and scores for the different age 

 groups are shown in Table 4. 



TABLE 4. 



Correlation between Milk Production and Score of Jersey Reg- 

 ' is try of Merit Cows for the Successive Age Groups. 



_-; Age at Commencement of Test 



Number of Correlation and Probable 

 Animals Error 



1 year 6 months-2 years 6 months 



2 years 6 months-3 years 6 months 



3 years 6 months— 4 years 6 months 



4 years 6 months-6 years months 



6 years -9 hionths-7 years months 



7 years months-9 years months 

 9 years months— and above 



190 

 144 



98 



94 _ _ _ 



37 



70 



39 



— 0.2117-K0467 

 — O.3088-H0508 

 — 0.1080+.0673 

 — 0.0608-K0693 

 — 0.0752-K1103 

 — 0.1863-4-.0778 

 +0.0345-K1079 



The data of this table show clearly that the cattle judge 

 can only select the high producing cow from her external con- 



3 It should be remembered that the individual scores are those of 

 Registry of Merit Cows which have year records of milk, butter-fat and 

 butter-fat percent. The scores are all by judges of recognized merit. 

 The scale of accuracy of judgment is taken as the correlation divided 

 by its probable error. 



