232 



The Journal of Heredity 



THE MEDIUM SIRE 



Figure 17. King of the Pontiacs has about 350 units of black and although medium in 

 appearance he bred more like a dark bull which was a hybrid, carrying latent factors for the 

 lighter grades of spotting. This famous sire has 280 registered daughters. Bred by Stevens 

 Hastings Co., Lacona, N. Y. Photograph courtesy of Mr. Stevens and the Holstein- 

 Fresian World. 



registry office believe the sketches to 

 be fairly accurate on the average. The 

 error in estimating the amounts of 

 black and white present in the coat is 

 probably not over five or ten per cent. 

 The Slotting of each side of the 

 animal is sketched separately on a 

 standard profile diagram. Our method 

 was to trace each sketch on onion skin 

 paper. We then prepared a duplicate 

 blank diagram on fine co-ordinate 

 paper. The area occujjied by the pro- 

 file diagram was about 950 squares. 

 The extent of the black and white 

 spaces on each animal could then be 

 estimated by ap])lying the onion skin 

 sketch to the ruled diagram and count- 

 ing the number of squares covered by 

 the black and white areas. This war 



done for both sides of all animals used 

 in this study. The results for each 

 estimation were then expressed as the 

 number of units or squares of black 

 on the animal. An all white animal 

 would then be grade 0, while an all 

 black one would be 950. The very 

 light bull in Fig. 15 is of grade 5U. 

 The units in this case are 950ths of 

 the total profile area of the animal, or 

 practically per milles. Dividing each 

 grade by ten reduces it roughly to per 

 cents. Thus King Model (Fig. 15) is 

 of grade 50 or roughly 5 per cent 

 black. 



The spotting grades of 294 animals 

 are used in this study, divided as fol- 

 lows : 



