No. 4.] 



DAIRY CATTLE. 



71 



tance of form and color much more nearly resemble the same 

 in the sire than in the dam. 



It is frequently remarked that the progeny of the first 

 cross shows less of improvement than was shown by their 

 parents. It could not be otherwise. When the parents were 

 mated, it would be correct to say that the difference between 

 them in blood elements would be represented by 100. At the 

 mating of the progeny of the first cross that difference would 

 be represented by only 25. There is not the same room for 

 effecting improvement, and it grows less with every succeed- 

 ing cross. On the basis of form, the following figures arbi- 

 trarily assumed will, it is believed, approximate the changes 

 in the successive crosses : — 



This means that in regard to form and color the animals 

 of the fourth cross would bear a close resemblance to the 

 breed from which the sires had been chosen ; in fact, in many 

 instances the resemblance would be so close that an expert 

 could not distinguish between grades and pure breeds. Thus 

 quickly can change be effected in form. Four to five genera- 

 tions of such breeding will thus obliterate the blood elements 

 of inheritance that at the outset pertained to the dams. 



The first mating in the case supposed brought to the prog- 

 eny an inheritance of 75 per cent of Holstein blood, and 

 in the mating of the animals of the second cross an inheritance 

 of 90 per cent of the same. Xow, suppose that the second 

 cross had been made with a Jersey sire. The inheritance of 

 Holstein blood would have been cut down about 37% per 



