Here is a summary of the paper given by Rogelio Prieto (summarised by an unknown author), along with another one given by someone else. It's a sustained metaphor on how "the British church (standing here for all Western ‘sending’ countries and their mission agencies) is a COW".
It's best to read the summary, rather than hear my summary of the summary, but here are some quotes to get you interested. (Bear in mind these are the unknown author's quotes from the original talks.)
Indeed if you are in need and as long as you look from a distance, the British church looks very cow-like – big and fat and promising, with irresistibly tender eyes.
If you’re in need and find a cow, you don’t study it...you milk it.