When it's hot and humid, you probably don't want to move much and aren't very hungry. The same goes for cows; but when they don't eat, farmers lose money.
Researchers at the University of Missouri think they can help avoid those losses. They've produced a new mobile app that can detect the threat of heat stress in cows using nothing more than a smartphone.
Weekend Edition Sunday is beginning a series of conversations with economists, asking them to explain their positions and what they think ought to be done to improve the economy. Guest host Linda Wertheimer talks to Greg Mankiw, former chairman of the Council of Economic advisers under President George W. Bush. He's also an informal adviser to the Romney campaign.