96 



CANADIAN FARM YEAR BOOK. 



derived from any one particular 

 strain. 



Inbreeding. — Line-breeding In- 

 volves the breeding together of 

 closely related Individuals. When 

 this practice is carried to Its limits, 

 and Involves the breeding together 

 of sire and offspring, or of dam and 

 offspring, or of brother and sister, it 

 becomes "Inbreeding," or "breeding 

 in and In." It has the same purpose 

 as line breeding, with rather greater 

 dangers, for it is line breeding car- 

 ried to the extreme. 



Heredity. — This term refers to the 

 extent to which the character oi the 

 parents and of their ancestors is 



transmitted to the progeny. No 

 question is of greater importance to 

 breeders, and no subject related to 

 breeding has been given more con- 

 sideration. It has been stated as a 

 law that "like produces like, or the 

 likeness of some ancestor." The in- 

 fluence of ancestors distantly re- 

 moved is too often overestimated. 

 Frequently too much stress is laid 

 upon the "foundation stock," and 

 not sufficient attention is given to 

 those from which the animal is more 

 directly descended. A reference to 

 the following table will illustrate 

 clearly that it is the top rather than 

 the bottom of the pedigree which 

 should be most considered. 



Generation Effec'ive contribution Number of ancestors Effective contribut'on 



backward of each generation involved of each ancestor 



1 1-2 2 1-4 or 25 p.c. 



2 1-4 4 



3 1.8 8 



4 1.16 16 



5 1.32 32 



Grading. — By this Is meant the rapid Improvement in the quality of 



mating of a common, or relatively common stock may be brought about. 



^^ ^ . By continuous mating in this way for 



unimproved, parent with one that Is g^^ generations, the percentage of 



pure-bred. It Is usual that the pure- unimproved blood remaining Is very 



bred parent Is the male. The prac- small. 



tice of mating "grade" females to The following table shows the rel- 



pure-bred males of the same breed ative amount of unimproved blood 



as that which predominates in their remaining in each generation up to 

 own breeding is one by which a'**the sixth: 



Sires Dams Offspring 



Generation pc. Purity p.c. of Purity p.c. of Purity p. c. of Unimproved 



1 100 50 (1-2) 50 (1-2) 



2 100 50 75 (34) 25 (1:4) 



3...:;......................... 100 75 87.5 (78) US l:\-S) 



4 100 87.5 93.75 (15.16) 6.25 (1-16) 



5 100 93.37 96.87(31-32) 3.12(1-32) 



6 100 9387 98.44(63.64) 1.56(1.64) 



Cross-Breeding. — This Involves the 

 crossing of two distinct races, as the 

 mating of a female of one breed with 

 a male of a distinctly different breed. 

 This practice is systematically car- 

 ried on in some districts, in the be- 

 lief that the offspring are superior to 

 the pure-bred " animals of either of 



the two breeds employed. It is not 

 usual for the progeny to be used for 

 breeding purposes, as in such a sys- 

 tem of breeding it is not advisable to 

 carry the operation farther than the 

 first generation. 



Prepotency. — This is a term by 

 which is expressed that quality which 



