Utilization of Heterosis in a Beef Cow Herd

George H. Shull, while working as a corn geneticist at the Cold Spring Harbor Laboratory from 1904 to 1915, observed that when two different pure-bred lines of corn were crossbred the resulting progeny exhibited physical traits superior to those of the parents (Glass, 2010). Shull described the offspring of pure-bred crosses as having increased heartiness, size, fruitfulness, speed of development, resistance to disease, resistance to pests, and resistance to climatic rigors when compared to the parent varieties (Edwards, 2005). Offspring resulting from crossbreeding two different varieties, breeds or even species are referred to as hybrids (MerriamWebster, 2011). The exhibition of the superior qualities exhibited by hybrids, George Shull called heterosis, other researchers called the condition hybrid vigour.