Terrance, Art, David, Lynda,

I wasn't going to say anything else until I finished reading the book.

I contacted the author of the book and learned, in summary, but not verbatim, that there are specific data establishing that many plantations in slave states in the mid-Atlantic were primarily focused on breeding and exporting bred slaves to the south and west. Virginia was the most active in establishing the legal and socio-economic structure to facilitate breeding. Jefferson was a major proponent of breeding and wrote about it often. The years following the 1808 Congressional Act outlawing participation in the international slave trade are considered by many historians of the topic as the height of the slave breeding era.
For infor on specific plantations, you might check out a dissertation written by Gerald Norde on slave breeding.

I found the following by Gerald Norde:
Norde, Gerald S. "From Genesis to Phoenix: The Breeding of Slaves During the Domestic Slave Era, 1807-1863 and Its Consequences."
Ph.D. thesis, University of Delaware, 1985.

Apparently a candidate for a doctorate submitted a dissertation on slave breeding.

Ed Adams