Genes that Aren't Blue
May 07, 2012
The current issue of The Atlantic Monthly has a great article about how understanding and unlocking the genetics of dairy cattle (and let’s be honest, it’s mostly about Holsteins in particular) has led to spectacular increases in the efficiency of those breeds, and in doing what they do best, which is making milk.
As the author, Alexis Madrigal, points out:
In 1942, when my father was born, the average dairy cow produced less than 5,000 pounds of milk in its lifetime. Now, the average cow produces over 21,000 pounds of milk.
There are a variety of reasons for this quadrupling of productivity, not all of them breeding related. Housing, feeding and animal care are the other key drivers. But as Madrigal describes in great detail how having a regimented system of scoring traits, along with meticulous records, has led to the ascendancy of a handful of Holstein lineages that are in great demand, the world over. It also has allowed us in the U.S. to make more milk with fewer animals, and attendant resources, which is at the heart of many arguments about how to define a sustainable system of providing consumer goods as the population, domestically and internationally, continues to grow.
To its credit, the Atlantic article also doesn’t shy away from some of the tradeoffs of the focus on milk output. Specifically, the author acknowledges that reproductive success (which is the sine qua non of successful breeding) is inversely related to milk output. More milk sometimes comes at the cost of making more calves. Most improvements in efficiencies in other sectors have similar tradeoffs. Smaller cars, for example, use less gas, but tend to be less safe in crashes. Electric cars use no gas, but cost a great deal more, and their power still has to come from somewhere, often coal-fired, on the grid. Free lunches are always hard to find.
And interestingly, Madrigal mentions that humans actually have a highly homogenous gene pool in comparison to Holsteins. At some point in prehistory, there weren’t that many of us around, and even with 7 plus billion people later, the home sapiens gene pool is as shallow as a sidewalk puddle.
Since the unlocking of the human genome more than a decade ago, we’ve been expecting the growing science of genomics to help us understand more about our strengths and weaknesses. So far, the results have been skimpy; deciphering the origins of disease, and unlocking the secrets to our longevity, are more daunting than was first assumed. But as we get more data, more will be learned. That’s been the case with cows, and humans won’t be far behind.