Dunn, Schneider and Webb: Spotting in Cattle 



235 



THE DARK BULL 



Figure 20. King Pietertje Ormsby Piebe 1659-1: has 900 units of black and only about 

 fifty units of white. This is probably the dominant type of spotting in Holstein cattle, al- 

 though this animal is not genetically pure for his spotting characters (see Figure 19). He 

 is the world's highest yearly record bull for both butter and milk production. Owned by 

 Hargrove and Arnold, Norwalk, Iowa. Photograph courtesy of the Holstein-Fresian World. 



all animals used." This correlation was 

 found to be very high (r=.971 1 .002). 

 There was almost perfect agreement 

 between the amounts of black on the 

 right and left sides indicating that we 

 were probably dealing with a general 

 variation of black pigment present and 

 that a description of one side of the 

 body could be used with almost perfect 

 accuracy as a description of the total 

 amount of black pigment in the whole 

 coat. Thereafter we used only the 

 amount of black pigment on the left 

 side as the spotting grade of the ani- 

 mal. 



We next determined the gross 

 amount of variation in spotting for the 

 whole series of 142 dams, since these 

 were taken as a random sample of the 

 breed. These cows ranged in amount 

 of black from about grade 10 (about 1 



per cent black) to about grade 925 

 (about 92 per cent black). The small 

 amounts of black in the lowest grades 

 were centered principally on the head 

 and particularly about the eyes, while 

 in the darkest grades the small 

 amounts of white appeared on the 

 lower legs and along the underline. 

 The absence of the extremes of self 

 white and self black is due to the re- 

 quirement of the association that ani- 

 mals eligible for registry shall be 

 black and white. The variation ap- 

 peared to be symmetrical and continu- 

 ous from the lightest to the darkest 

 grades. The mean grade of this ran- 

 dom sample of cows was 433 units 

 (about 43 per cent black) or slightly 

 less than the mean of the possible ex- 

 tremes (475 units). This is perhaps 

 due to a sexual difference since it is in- 



"In this correlation and wherever biometrical methods were used we grouped the in- 

 dividuals in classes of 50 units, viz.: 0-49 units of black; 50-99 units, etc. 



