IMPROVEMENT OF ANIMALS 261 



native. A high grade animal is one which is more than half 

 pure bred. Native stock are those in which there is no certain, 

 traceable blood of any special breed. They may be a mixture 

 of several breeds. They are often called " Scrubs." 



Cross-bred animals are the result of crossing two pure- 

 bred animals of different breeds, as a Holstein Jersey cross 

 in cattle, or a Plymouth Rock Cochin cross in poultry. 



Pedigrees. These are statements of the lineage or ances- 

 tors of animals. Records are kept of all the animals of 

 the pure breeds, if the owners care to register them. Owners 

 of stock of a certain breed form an Association, the officers 

 of which establish herd books in which records are kept of 

 the animals and their offspring owned by the members. 

 (See the sample Holstein pedigree in the Appendix.) 



EXERCISE. Stock Pedigrees. Some pupils in the school 

 may be able to bring to the teacher a written or printed 

 pedigree of farm animals owned by some one in the neighbor- 

 hood. Tne value of such a complete record may then be 

 made clear to the class, because of its local application. 



Bad Effects of Crossing. It is far too common a practice 

 for farmers to cross the stock of two breeds. Where a herd 

 is graded up toward one breed, as Jerseys, they are then 

 crossed with Holsteins or Shorthorns, the hope being to 

 increase the quantity of milk. The result is usually a dis- 

 appointment and the practice is a bad one. When there are so 

 many good breeds of each kind of farm animals it is unwise to 

 try to blend them by doing such crossing. Instead of a 

 blending effect, the stockman often gets the extreme charac- 

 teristics emphasized by close contrast in one individual. 

 For example, the head, hairy feet and legs, and large hoofs of 

 the Clydesdale are sometimes found on the slender body of 

 a race-horse. The more extreme the crosses or the greater 

 the difference in type between the breeds used in the cross, 

 the greater will be the number of failures. The successful 

 crosses are few. Occasionally the bad effects of a cross do 



