Reference “The Well-being of Farm Animals” online, Grazing Animal Vision pg.123. Research indicates they are dichromats most sensitive to yellow-green and blue-purple light, especially sensitive to motion and high contrasts.
Vicky, bingo! thanks a bunch; exactly what I had been looking for…… had a very similar chapter in one of temple grandins books…. your link is fascinating, connecting into other animal behaviours as well elke