INHERITANCE OF COLOR IN PERCHERON HORSES. 



273 



ences are slight and consistent in case of both colts and fillies in 

 making the dam more prepotent when older and correspondingly 

 the sire less subpotent when older. 



In order to see whether there appears to be an optimum age 

 of prepotency the data have been arranged in a number of tables 

 that follow. In the mating of domestic animals a greater variety 

 of crosses with regard to the respective ages of the parents is of 

 course met with than in man. In marriage the man is ordinarily 

 older, but among horses we have all possible combinations occur- 

 ring frequently. 



In arranging the data to determine if there be an optimum age 

 the parents have been grouped as follows : I., very young, 3-4 

 years old. II., young, 5-7. III., medium age, S-io. IV., 

 older, 11-13. V., very old, 14 and over. 



In Table VII. which follows are given all cases in which dams 

 were mated with very young sires. 



TABLE VII. 



When the sire is very young 58 per cent, of the colts and 60 

 per cent, of the fillies resemble the dam, or the prepotency of the 

 dam is 59 per cent, as against the average prepotency of 54 per 

 cent, derived from Table II. 



Naturally we would take next for consideration the prepotency 

 of dams mated with very old sires, 14 and over. There were 

 only 70 such cases in the 2,000. They show that 66 per cent, 

 of the colts and 63 per cent, of the fillies resemble the dam, an 

 average prepotency of the dam of 64 per cent. 



TABLE VIII. 



