In a 3-year study at 6 locations in Louisiana with 1714 beef cattle the effects of diets of maize silage or forage [wheat or rye with Lolium multiflorum or Cynodon dactylon and Trifolium repens, Trifolium pratense and Trifolium vesiculosum] on the wt and quality of carcasses were studied. Steers and heifers finished on silage had heavier carcasses with greater fat thicknesses, higher quality grades, higher numerical yield grades, whiter fat and a greater market value/lb of carcass wt than cattle finished on forages. Steers finished on forages in summer had less fat and lower quality grades than forage-finished steers in winter.