at the start of the game on my way to whiterun from riverwood i encountered an odd looking cow with what looks like tribal markings on it and decided to follow it and see where it went, before long i realised i could be following it all day and decided to get on with the game anyway loads of quests and level ups i was walking through the woods in the middle of night up north near morthal when i caught a glimpse of a bear crossing my path, i got ready for a fight when i realised it was the same cow, i then also encountered a farmer being attacked by spiders after all he would say was something about getting a new one (cow?), i cant remember exactly what he said but i think he was involved with that cow.

anyway is this just an easter egg or related to a quest later on?

It's a gift cow, you occasionally see farmers escorting them to giants camps. That one must have run away.