Grass-fed butter is superior to grain-fed butter & better for your health. It is yellow in colour because it is rich in natural beta-carotene & vitamin A. It is higher in vitamin K2, has an equally balanced fatty acid composition & the cows are not given antibiotics or growth hormones. Kerrygold & Anchor butter are two easily accessible grass-fed butters, which I will be switching to. Thanks to my client, Sue for informing me.