Yes, there are notable differences between fully grass-finished and grain-finished cattle, even if both started grass-fed:

Grass-Fed, Grass-Finished:

- Maintains consistently high omega-3 levels throughout the animal's life

- Higher CLA levels are preserved

- Leaner meat overall with less total fat marbling

- Deep yellow fat (from beta carotene in grass)

- More vitamin A and E retained

- More consistent mineral content

- Better omega-6 to omega-3 ratio (typically around 2:1 to 3:1)

Grass-Fed, Grain-Finished:

- Omega-3 levels drop during grain finishing period

- CLA levels decrease with grain feeding

- More marbling and intramuscular fat

- Whiter fat (less beta carotene)

- Lower vitamin A and E content

- Slightly altered mineral profile

- Higher omega-6 to omega-3 ratio (can rise to 5:1 or higher)

The key difference is that grain finishing, even after grass feeding, partially reverses many of the nutritional benefits accumulated during the grass-fed period. The finishing period typically lasts 3-6 months, which is enough time to significantly alter the fat composition and nutrient profile of the meat.

However, grain-finished beef does typically provide more marbling, which some people prefer for taste and texture. It's worth noting that even grass-fed, grain-finished beef is still generally more nutritious than conventional grain-fed beef from start to finish.