over the past decade, the dairy industry has embraced big data, sequencing thousands of dairy cows to pinpoint the genetic markers that correlate with prodigious milk production.
Chief—let’s call him Chief for brevity’s sake—was so popular because his daughters were fantastic milk producers. He had great genes for milk. But, geneticists now know, he also had a single copy of a deadly mutation that spread undetected through the Holstein cow population. The mutation caused some unborn calves to die in the womb. According to a recent estimate, this single mutation ended up causing more than 500,000 spontaneous abortions and costing the dairy industry $420 million in losses.