I have spent the last couple of hours looking for this census.
According to information at
http://www.rootsweb.com/~iachicka/CK_Census4.htm#1875, the census "was a statistical census only and, by comparison with all the other State and Federal schedules ... not as beneficial to the family history researcher. One other disadvantage of the 1875 Iowa State Census is that it is not as readily available..."
The last part of this statement is definately true. Neither FHL or IA Gen Soc libraries have it. I did find a copy at the Minnesota Historical Soc library, but doesnt appear to be loanable.
I would like to know, from someone who has direct knowledge of this publication, whether or not it is of any genealogical use.
Gary