From the outside, the basics of the question seem obvious. Grass-fed cattle have eaten grass and grain-fed cattle, well, you get the picture.
Grass-fed vs grain-fed beef from a butcher's point of view
Taste the Difference: Grass-Fed vs. Grain-Fed Beef – One Stop Halal
GRASS-FED vs GRAIN-FED steak experiment which is best?
Grass-Fed vs. Grain-Fed Beef: Are There Benefits?
Grass-Fed vs. Grain-Fed Beef — What's the Difference?
Why You Should Choose Grass-Fed Beef
What is Angus beef and why is it in so many burgers? - Steak School by Stanbroke
GRASS-FED vs GRAIN-FED steak experiment which is best?
GRASS-FED vs GRAIN-FED steak experiment which is best?