Dunn, Schneider and We1)l) : Spotting- in Cattle 



233 



AVERAGE DARKNESS OF MEDIUM BULL'S OFFSPRING 



Figure 18. Alcartra Johanna Korndyke 415274 shows the average grade of the daugh- 

 ters of King of the Pontiacs when mated to cows of all grades. The cows with which 

 King of the Pontiacs were mated averaged 200 units (about twenty per cent) darker than 

 the cows with which the other two bulls were bred. Photograph courtesy of the Blooming- 

 dale Farms. 



(1) A lig-ht bull (King Model) 

 Figure 15 : 



46 cows mated to King Model 

 and 50 offspring (25 males 

 25 females) resulting from 

 these matings, including one 

 pair of twins and two off- 

 spring each from three cows. 



(2) A bull of medium grade (King 

 of the Pontiacs) Figure 17: 



49 cows mated to King of the 

 Pontiacs and 49 offspring (25 

 males and 24 females) result- 

 ing from these matings. 



(3) A dark bull (King Pietertje 

 Ormsby Piebe) Figure 30: 



47 cows mated to King Pie- 

 tertje Ormsby Piebe and 50 

 offspring (25 males and 25 



females) from these matings, 

 including 1 pair of twins and 

 two offspring each from two 

 cows. 



The cows which had been mated to 

 each bull were chosen by serial regis- 

 try numbers in order that a random 

 sample in respect to spotting might be 

 secured. In order to secure an equal 

 number of male and female offspring, 

 the dams of the first twenty-five off- 

 spring were chosen as dams of female 

 calves and the second twenty-five as 

 dams of male calves. 



Analysis of Data 



In order to simplify the treatment 

 of the data, we first determined the 

 correlation between the amounts of 

 black on the two sides of the body for 



