80 MANUAL OF FARM ANIMALS 



show a high tendency to reproduce their characteristics have 

 secured these quahties from a comparatively short line of 

 animals noted for their breeding qualities. It would be difficult 

 to trace the actual influence of the parents back of the fourth 

 or fifth parents, in a number of cases. It is the individuals 

 making up the pedigree for the last four or five generations that 

 are of great influence in giving any individual the power to trans- 

 mit quahties ; and if all of the individuals constituting the 

 pedigree for these generations have the qualities that we rec- 

 ognize as good, we may count upon the animals transmitting 

 their qualities with such a degree of certainty that it makes 

 little difference what the individuals were back of that point. 



Of late there has been much discussion as to the part 

 each ancestor contributes in the total heritage. Galton was 

 one of the first to answer this question. While he answered it 

 with much hesitation, his suggestions received considerable 

 support and have come to be known as "Galton'sLawof ancestral 

 heredity." Galton set forth the idea that one-half of the full 

 heritage comes from the parents; one-fourth from the grand- 

 parents ; one-eighth from the great grandparents ; one-sixteenth 

 from the great, great grandparents, and so on to infinity. 

 This being true, an offspring will procure f^ of its full heritage 

 from the five nearest generations of ancestors. 



In selection, the performance of the animal, when available, 

 as it is in race horses and dairy cows, should also be considered. 

 The record of performance affords very valuable information 

 as to what the offspring will probably be like. When breeding 

 dairy cows, if one unites two animals of low-producing strains, as 

 shown by the records, his chance of procuring a high-producing 

 result are not very great. On the other hand, if one unites 

 two animals of high-producing strains, as shown by the records, 

 his chance of procuring a high-producing offspring are very good, 

 although not sure, as there may be a certain influence of the 

 heritage from the very early ancestors whose records were not so 



