184 THE PRINCIPLES OF BREEDING 



most likely to follow hybridization, and is exemplified by the line 

 back and leg strii:)es commonly seen on mules. 



A pure bred is, practically, one whose sire and dam are both 

 registered. The " purity " of the breeding depends upon the 

 eligibility rules of the respective registry associations. Lit- 

 erally, a pure bred is one in whom there is no trace of alien 

 blood, but such a degree of purity is approached only by the 

 breeds of greatest antiquitj^, as the Thoroughbred and the Arab. 



Grading up is the mating of common bred mares to pure bred 

 stallions, or the reverse, producing half-breds. By mating the 

 half-breds back to pure breds, of the same breed, the percentage 

 increase of the pure blood will follow the proportions of three- 

 quarters, seven-eighths, and so on, for each successive generation. 

 A horse so bred is called a grade, and the greater the number of 

 generations through whicli the grading-up process has been car- 

 ried, the higher the grade. 



A mongrel or scrub is one whose fractional breed identity 

 c-annot be established. 



Top cross refers to the male line of ancestors — the sire's sire, 

 his sire, and thus on back. 



Dams. — First, second, third, and fourth dams represent the 

 female line of ancestors — the dam's dam, her dam, etc. 



Brothers in blood are the progeny of mating full brothers 

 -\\ith full sisters, tlie same stallion with full sisters or the same 

 mare with full brothers. In each case the mating results in in- 

 dividuals whose pedigrees after the first generation are identical. 



Pedigree and Studbook Registration. — In order to keep 

 pedigree records complete and accurate, as well as reliable and 

 authentic, registry associations representing the different breeds 

 have been formed. Entries are made in either alphabetical or 

 numerical order, and show the name, date of foaling, description, 

 breeder, and owner of the horse, with the name and number of 

 sire, and name, number, and usually some of the breeding of 

 the dam. These records are published in book form at more or 

 less regular periods, annually, if the association does sufficient 

 business, and are available to any one at a nominal charge. 



Transfers of ownership of registered horses are required to 

 be recorded for the purpose of keeping all records up to date. 



