Madeline, unfortunately I cannot find out more about the reproductive loan records. John Grenham's book certainly gave me the impression there are more lurking in the Kew Archives given that these records extend from the 1820's. However I went to the library yesterday and looked at microfiche of the Kew Lists and under reference T 91 it didn't show me anything that looked like Schedule C, Supplementary Statements, or townland returns for any places in addition to what was already digitized. So now I don't know what to think.
You might want to take a look here:http://discovery.nationalarchives.gov.uk/SearchUI/browse/C13...
There are other subseries of T 91, e.g., balance books and petty expense books but only for Cork areas represented in 142A and 142B.
It would require visiting Kew I imagine. You would have to ask specifically about records for Cork other than the late famine-era records that have already been digitized and put online that contain borrower data.