70 BOARD OF AGRICULTURE. [Pub. Doc. 



Improvement by grading tip. 



Improvement by grading means that only sires of one pure 

 breed shall be used during its continuance, and that the im- 

 provement secured will be strengthened from time to time 

 by calling out and rejecting for breeding uses any inferior 

 animals that may appear. And just here it may be said 

 that, as a rule, the more common or mixed the blood elements 

 in the foundation females when such improvement begins, the 

 more rapid relatively the improvement. The explanation is 

 not difficult. By this system improvement is mainly sought 

 through the male. His power to effect change in the line 

 sought comes from his prepotency, and his prepotency from 

 his inheritance. The more prepotent the sire, the more 

 rapidly will he effect improvement. 



The improvement sought comes mainly from the sire. 

 Each additional infusion of alien blood in the near ancestry 

 of the cow weakens her potency in transmission. In other 

 words, it aids potency of transmission in the male by weaken- 

 ing the resistance in the female. When, therefore, the ordi- 

 nary owner of cows sets out to seek improvement, usually he 

 cannot do better than use such stock as he has to begin with ; 

 but the males introduced ought to be good individually, and 

 chosen successively from the same breed. 



See how quickly improvement may be effected. Suppose 

 the foundation females are of the class described, and that the 

 sires chosen for the improvement sought are of the Holstein- 

 Eriesian breed. According to the theory that the male is half 

 the herd, 50 per cent of the elements of inheritance would 

 come from the sire, and a similar per cent from the dam. 

 But the prepotency of the male is much greater than that 

 of the female, for reasons given. More than 50 per cent of 

 the elements of inheritance will come from the sire. The 

 preponderance in the elements of such inheritance will be 

 proportionate to the preponderance of potency in the sire. 

 While no one can state in any given instance the mathematical 

 proportions of the inheritance, it would seem safe to conclude 

 that 75 per cent at least of these elements have in the case 

 supposed come from the sire. This explains why the inheri- 



