Breeding 435 



sometimes called, therefore, germinal variations. The 

 several eggs produced by the sow when she comes in heat 

 are not alike, especially if she is of mixed breeding. As 

 a rule, the more uniform the type of the animals in the 

 sow's pedigree, the more uniform will be her eggs with 

 respect to this character; the more dissimilar the types 

 in the pedigree, the greater will be the germinal variations 

 among the eggs produced. In the same way, the sperms 

 produced by the boar vary with respect to any and all 

 characters to the same degree that the individuals in his 

 ancestry vary in these same characters. When ten sperms 

 unite with ten eggs in the process of fertilization following 

 breeding, the chances for variations among the pigs which 

 develop from these eggs are still further magnified. If 

 variations are reasonable among pigs of the same an- 

 cestry, it is obvious that pigs of dissimilar parentage, for 

 the same reasons would normally present even greater 

 variations. 



Variations of this kind are of fundamental importance 

 to the breeder because without them improvement would 

 be impossible. It was through the selection of the desir- 

 able hereditary variations and their correct combination 

 in mating that all breed improvement has been brought 

 about. Observations of the breeder have shown that some 

 variations are desirable and some undesirable, the larger 

 number being undesirable. There is always the tendency 

 in pure-bred herds, therefore, for the offspring to be in- 

 ferior to their parents. In other words, pigs produced 

 by prize-wirming parents are not so good, on the average, 

 as the parents themselves ; a few may be better, but most 

 are inferior. A clear appreciation of this fact on the part 

 of young breeders especially will insure less frequent oc- 

 currence of disappointing results. 



