Current Cow Breeding Methods Could Lead to Their Extinction

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