Kerry gold butter is grassfed year round and has all the increased nutrients, normal butter is not orange. It still has vitamin A in it or the butter would be white. I don't think colour is a good guide by itself.
The fact that the butter is soft is a sign that it is from grassfed cows. The butter from grass fed cows has less saturated fat and and more unsaturated fats like alpha-linolenic acid and conjugated linoleic acid which have lower melting points making the butter softer.
Edit: PortlandAllen is correct the Irish cows would be fed hay or silage over the winter. Although Irish cattle can graze longer than most others in Europe or America due to the warmer, wetter climate. If you want butter from year round grass fed cows you'd have to get some New Zealand butter.
How do we make the richest smoothest creamiest-tasting butter?
We start with 100% fresh cream from cows that graze only in green pastures 365 days a year. We add nothing but a touch of salt. The fresh cream is slow churned torelease the water and then packed into blocks that are immediately frozen, locking in the freshness and rich buttery flavor. Butter from grass-fed free-ranging cows is higher in Omega 3, Vitamin A, and Beta Carotene, all proven to be good for your health. Additionally, our daily cows are absolutely hormone free.