Animal Husbandry Investigations in 1919. 269 



startling clearness the need of exact knowledge of the trans- 

 mitting qualities of bulls to be bred as sires and of the necessity 

 for exact knowledge of the inheritance of milk production and 

 butter-fat percentage. 



The inbreeding coefficients show that the sires of superior 

 merit are 7.08 per cent of the greatest possible inbreeding up 

 to the fifth generation. The inferior sires are inbred 9.65 per 

 •cent of the greatest possible amount (continued brother and 

 sister mating). The group of sires poorer in their transmitting 

 •qualities are consequently more inbred than the group of sires 

 with superior transmitting qualities. 



The analysis of the pedigrees for the amount of relation- 

 ship that may exist between the sires and dams of the individual 

 bulls in the superior group and in the inferior group shows 

 that there is little or no difference in the amount of this rela- 

 tionship within the two groups. 



The resolution of the four generation pedigree into the 

 Island bred Jerseys and by difference American bred Jerseys 

 showed the mean number of Island males in the pedigrees of 

 the superior sires group to be 8.07 and the mean number of 

 females 7.79. The mean number of Island bred males in the 

 inferior sires group were shown to be 6.94 and the mean num- 

 ber of females 6.55. The group of sires which increased the 

 production of their daughters over that of their dams had, con- 

 sequently, more Island bred stock in their pedigrees. The fe- 

 males in each group of the pedigrees had a less proportion of 

 Island bred individuals than the males had in each of the 

 groups. 



This same information on Island bred animals is revealed 

 when classified as to whether the animals occur on the sire's 

 or dam's side of the pedigree that the superior sires have by a 

 small percentage more Island bred animals in the sire's side 

 of their pedigree than do the inferior sires and that the superior 

 sires have a larger number, probably significantly larger num- 

 ber of Island ancestors in the female side of the pedigree than 

 do the inferior sires. The figures are 8.82 to 8.19 and 7.04 to 

 5.30. The number of ancestors of Island breeding on the 

 sire's side of the pedigree is in both cases larger than the num- 

 ber of Island bred ancestors on the dam's side of the pedigrees. 



