New York Times: For six years, while drought ravaged Chihuahua State, Mario Ruiz clung to his small herd of cattle. The pasture where his cattle graze, about 45 miles north of the city of Chihuahua, turned bare. Many of his cows starved. Others he sold to buy fodder for those worth saving. Of 130 cows, just 30 are left. Now that the rains have returned, turning the dusty steppe a rich green, farmers like Mr. Ruiz, 41, are struggling to restock their herds and dig themselves out of debt. They fret that the drought,...