Use OR to expand your search: 1) feed* or ration* or supplement*;
2) cattle or cow or cows or bull or bulls or steer or steers or heifer*;
3) soybean* or soyabean* or glycine max
Think carefully if use NOT -- you may eliminate important items.
Be aware:
-- Not all journals are available electronically;
-- The years of coverage available electronically varies widely;
-- The number of clicks it takes to get to the actual article varies also... from one to ten, and depends on how the access is set up.
To see All available databases, go to the Databases LibGuide.