Improving Goat Production In The Tropics

Improving Goat Production In The Tropics by C.P. Peacock discusses ¨Methods of feed analysis on page 72 of the google book

Sheep Feeding Programs: Forage and Feed Analysis

Although specific for sheep, this provides information about steps to analyse feed including choosing the feed, collecting a sample of it, submitting the sample and choosing the nutrients to analyse. It also has literature for reference.

Feedstuff

Feedstuff is basically animal feed as an uncountable noun. As a countable noun, it refers to any such animal feed.