Which preposition to use with inbreeding

with Occurrences 1%

There is a white blaze on the forehead, in the centre of which should be a clear lozenge-shaped chestnut spot, called the beauty spot, which by inbreeding with other varieties is fast being lost.

of Occurrences 1%

The black and tan thereupon went quite out of favour, and this fact, coupled with the reckless amount of inbreeding of red to red that has been going on since Ptero's day, accounts largely for the prevalence of light eyes, pink noses, and bad-coloured coats of the Dachshunds, as a class, to-day.

Which preposition to use with  inbreeding