Hereditary Colour in Horses

Abstract

MY attention has been drawn to a collection of data on the hereditary transmission of colour in horses, which appeared in the last Christmas Number of the Horseman, a newspaper published in Chicago, U.S. It is signed with the pseudonym of “Tron Kirk.” I corresponded with the author, who is noted for his knowledge of horse-breeding, and he assures me of their substantial correctness. His statistics are chiefly obtained from breeders' catalogues, and, however valuable in other ways, fail seriously through the great disproportion which must exist between the number of the different sires and that of the dams, a single sire in the polygamatous arrangements of a stud begetting a numerous offspring from nearly as many dams. It is stated that no less than 3100 foals were begotten by only 46 different bay sires, or more than an average of 67 foals by each sire. Now the number of offspring of the 16 different forms of colour union registered in Table I. is, with one exception, by no means large; in 9 cases it is less than 100, and in one of these it is only 6. Consequently the prepotencies, or the reverse, of individual sire will fail to balance each other, and are sure to produce anomalous results.