Six weeks earlier, on a breezy April afternoon, Katy and her family sat on horseback on the rodeo grounds as a small crowd of elected officials and conservationists celebrated the preservation of 374 acres of pasture they own here. In a nearly $3 million deal, they sold the development rights to the New Jersey Conservation Foundation of Far Hills, Somerset County, ensuring it will never be built upon or even tilled for crops — although the family can continue ranching on it.