Current Cow Breeding Methods<br />Could Lead to Their Extinction In the United States, there are<br />more than nine million dairy cows. A majority of these cows are large bovines with<br />black-and-white markings, known as Holsteins. Researchers have found that more than<br />99% of these male Holsteins trace back<br />to one of two cows from the 1960s. This means that only two Y chromosomes exist<br />among all male Holsteins in the United States. Female holsteins haven’t fared well either,<br />with the population’s genetic similarities making<br />the effective population size less than 50. This amount of inbreeding leads to<br />genetic homogeneity, which increases<br />the risk of inherited disorders. The “inbreeding coefficient” for Holsteins<br />is currently about 8% and has continued<br />to increase by around .4 every year. Inbreeding reduces the population’s ability<br />to evolve, inhibits fertility and lessens their<br />ability to fight diseases in the future.
