N"o. 645] 



COEFFICIENTS OF INBBEEDING 



337 



By this means the inbreeding in an actual pedigree, 

 however irregular the system of mating, can be com- 

 pared accurately with that under any regular system of 

 mating. 



As an illustration, take the pedigree of Eoan Gauntlet, 

 a famous Shorthorn sire, bred by Amos Cruickshank. 

 This bull traces back in every line to a mating of Cham- 

 pion of England with a daughter or granddaughter of 

 Lord Eaglan. For the present purpose we will assume 

 that these bulls were not at all inbred themselves and 

 not related to each other. Since the sire traces twice to 

 Champion of England and twice to Lord Eaglan and the 

 dam once to each bull, there are in all four lines by which 

 the sire and dam are connected. 



Roan Gauntlet 



The coeflicient of inbreeding comes out 14.1 per cent., 

 a rather low figure when compared to such systems as 

 brother-sister mating (one generation 25 per cent., two 

 generations 37.5 per cent., three generations 50 per cent., 

 ten generations 88.6 per cent.) or parent-offspring ma- 

 ting, (one generation 25 per cent., two generations 37.5 

 per cent., three generations 43.8 per cent., approaching 

 50 per cent, as a limit). 



As an example of closer inbreeding, take the pedigree 

 of Charles Collings ' bull, Comet. The sire was the bull 

 Favorite and the dam was from a mating of Favorite 

 with his own dam. As Favorite was himself inbred to 

 some extent, it is necessary to calculate first his own 

 coefficient of inbreeding. 



