Why were hundreds of cattle slaughtered in Brazil?

Authorities in Brazil say they have completed slaughtering hundreds of cows in one of the country’s key cattle states in a move to prevent the spread of hoof-and-mouth disease.
   Police supervised the slaughter of more than 200 head of cattle in Rio Grande do Sul state Thursday. The carcasses were buried in large open pits.
   Brazilian officials have expressed optimism that they have stemmed the spread of the highly contagious virus, which was discovered in 11 Brazilian cattle earlier this month.
   The European Union, Chile and several Arab state., have suspended imports of beef from Rio Grande do Sul, which is responsible for nearly 10 percent of Brazil’s beef exports.
   The government says it plans to compensate the ranchers for their lost livestock.