I remember being told that St. Brigid was associated specifically with red cows and that often the eldest red milk cow of a herd is called "Bridey" (one of her nicknames) in her honor.

There's an interesting image of St. Brigid to be seen above the doorway of the tower that stands on the summit of Glastonbury Tor. It's a stone bas relief above and to the left of the western doorway of the tower. If memory serves, you can make out a cow in the image. (The tower is all that remains of a church, dedicated to St. Michael, destroyed by an earthquake many centuries since.)