This Spring, we have a ewe lamb with a lot of tan splotches of color throughout her wool, really lovely, and yet another variation on the many possiblities to expect when breeding Icelandic sheep. In the years I have been raising these sheep, I have become fascinated with the seemingly endless variations on potential colors and patterns.
There are basically three factors that determine the appearance of a sheep, Pattern Factor, Color or Pigment Factor, and the Spotting Factor. The color in the wool is caused by pigment called eumelanin (the black and moorit (brown)). There is also pigment called phaeomelanin which can be shades of tan yellows, or rusty reds.
Lambs born with phaeomelanin look rusty color at birth, however the pigment fades with age in the fleece. The head and leg continue to exhibit the color. You will notice this on many mature white sheep on their heads, tails and legs. In Iceland, it was believed that sheep with this tan had better meat conformation, so it is quite common.
The pigment gives the fleece a rich linen color—just another beautiful shade for the handspinner who prefers to work with the natural colors of sheep.