Why are cows more productive?

I've written frequently about the incredible productivity gains witnessed in agriculture, and I often mention such statistics in talks I give.  

But, what does the average person think when they hear this sort of evidence?

I decided to find out.  In the latest edition of the Food Demand Survey (FooDS), I provided respondents with some statistics on increased productivity in dairy production based on some data compiled by Bailey Norwood (I should note that Bailey mentioned that he is revisiting these figures, and thinks current water usage is likely higher than 2 gallons) .  

Here's what was asked:

In 1945, it took about 10 gallons of water and 50 lbs of feed to produce a gallon of milk. Today, it only takes about 2 gallons of water and 10 lbs of feed to produce a gallon of milk. Each dairy cow today produces about 200% more milk compared to one in 1960. How do you think this change happened?

People were then prompted to provide an open-ended response.   They could type anything they wanted.

As you might suspect, answers were all over the board (a complete, unedited list of the more than 1,000 responses is here) from "Witchcraft" to "corruption" to "I have no idea".

A keyword search was conducted among the open-ended responses.  Some of the main keywords mentioned were: hormones (69), growth hormones (41), feed (28), technology (25), and selective breeding (20). 

Looking through the responses it seems some variation on "hormones" ("hormones" or "growth hormones" or "steroids" or "drugs") were particularly common.  This is interesting because hormones aren't much used in milk production.  Some dairy cows are given the hormone rBST to boost production, and adoption of the increased in the 1990s and peaked sometime in the early 2000s and then has fallen off since then.  According to one USDA source, only about 22% of cows in the US received rBST in 2002. This paper reports that only 9.5% of dairy producers used rBST in 2010.  Thus, there appears to be something of a disconnect between how people think productivity gains occur vs. the reality on the ground.

Individual responses were placed into seven different categories related to:

  • hormones (134 responses)
  • feed chooses (78 responses)
  • science (61 responses)
  • breeding and genetics (61 responses)
  • drugs and steroids (30 responses) 
  • farming techniques (27 responses)
  • economics (6 responses)
  • others

You can read more about the responses in latest edition of FooDS.