It appears that homosexuality is common in the animal world as it is in the human world. I was reading David McCumber's book, The Cowboy Way, and in the spring, cowboys determine when the heifers are going into estrus by taping a packet of red dye to their backs. When a heifer goes into estrus, she is mounted by the other heifers. They break the packet and the red dye is spread on the flanks. Then, the cowboys know to separate that heifer over with the other breeding ones and initiate artificial insemination.