Studies in Milk Secretion 151 



tors up to and including the fourth generation in the sire's or 

 dam's side of the pedigree is fifteen. There are eighteen sires 

 of pure island breeding on their father's side. Four other sires 

 have practically complete island breeding. The sires of supe- 

 rior transmitting qualities have 14 sires practically island bred 

 on their sire's side. This in proportion to the number of each 

 group means that the superior sires have a larger amount of 

 island breeding than do the sires in the inferior group. 



On the dam's side of these pedigrees there are twelve with 

 complete island breeding and two lacking only one individual. 

 The pedigrees of the sires which raise the production of their 

 daughters contain eleven sires whose dams are of strict island 

 breeding. The amount of island breeding found in superior 

 sires is consequently greater than is the amount found in the 

 sires which lower the production of their daughters when the 

 relative number of the two classes of individuals is considered. 



These facts are borne out by the percentages for the whole 

 pedigree and for the great-great grandparents. The sires 

 which raise the production of their daughters over that of their 

 dams contain up to the fifth ancestral generation more island 

 breeding than do the sires which lower the production of their 

 daughters over that of their dams. In both groups of sires 

 shown in tables 10 and 11 there are more island bred bulls than 

 cows. The sire's sire shows more island bred stock in his pedi- 

 gree up to the fourth generation than does the sire's dam. 



Animals Repeated in the Pedigree of the Sires which 

 Raised the Production of their Daughters. 



If we accept provisionally the old saying that, "like begets 

 like" it should follow that the ancestors within the pedigree of 

 superior sires should themselves be worthy animals. If a 

 pedigree study of a group of such superior sires is made, the 

 animals most repeated in a given generation should be the best 

 animals for they have the greatest opportunity to transmit high 

 production to their progeny which is known to carry high pro- 

 duction. Some insight should be gained, as to the worth of a 

 given animal by such a study even though the animals may not 

 have any other obtainable record. This is especially true in 

 connection with this study since the pedigrees of the sires which 





