The “Butter-Cow Lady,” Norma Lyon, whose famous sculptures made out of butter helped propel her to national fame, died Sunday in Iowa. The cause of death was a stroke, her family said. She was 81. Lyon began sculpting with butter at the 1960 Iowa State Fair, when she became the official sculptor of the Butter Cow, the dairy industry’s symbol. From 1960 until her retirement in 2006, Lyon’s sculptures, including The Last Supper, brought in huge crowds. She was so famous that President Obama sought her endorsement in 2007. After they met, she used 23 pounds of butter to sculpt a bust of Obama. She also produced a 60-second radio commercial for him, which has been credited with helping Obama win the influential Iowa Caucus in 2008.