284 Maine Agricultural Experiment Station. 1919. 



thing in the first part of the lactation the milk yield of the high 

 breed. The rapid decline of the seventh and eighth months 

 would make it seem that this cow inherited some of the tendency 

 to a short lactation like that of her sire's breed. 



The results herein presented may be summarized in two 

 brief statements. 



(i) When a mating is made between strains of high milk 

 producing ability and of low milk producing ability, the milk 

 production is likely to fall somewhere between the two parents 

 but will most nearly be that of the high producing parent. One 

 exception more apparent than real may be said to occur in 

 Crossbred No. I milk yield. This case, however, probably fol- 

 lows this same law in that Pauline Posch herself may have a 

 high milk producing inheritance from one side and a low milk 

 producing inheritance from the other. If this is granted it is 

 not strange that when mated to a lower milking breed, that this 

 lower inheritance of Pauline Posch should meet the lower of 

 the milk producing inheritance of the lower breed when bred 

 to a calf of lower milk yielding capacity. 



(2) The milk yield . of the breeds seem to occupy the 

 following relation : The low milk yield of the Aberdeen Angus 

 is recessive to the higher milk yield of the Jersey. The Jersey 

 milk yield is recessive to the higher milk yield of the Holstein- 

 Friesian. 



The application of these results to the pure breeding work 

 seems too obvious to mention. Among other things these results 

 show why a bull from the mating of two high producing strains 

 may be very disappointing as a transmitter of milk production. 



