[Cob] Horse vs cattle manure (for earthern plasters)

[Mitch Ventura]

I remember reading about horse manure having more fiber than cattle (due to a different digestive system), but that cattle manure has more enzymes that helps bond the plaster to a wall; the author said that it is best to mix both 1:1. Can anyone send me a bibliographic reference? (An architect who `presented a local workshop that I participated in recommended only using horse manure, and wants to know about the advantages of mixing it with that of cattle.)