SYLVANIA - If diamonds were the theme for the 60th anniversary of Screven County's Livestock Festival, then they couldn't have glistened more in Saturday's record high temperatures, at what has become the longest continuously running livestock festival in Georgia. Edward and Thetis Brinson, selected as 2011 Grand Marshalls for the parade, have been farming as long as Screven County has celebrated livestock. Long-time Screven County residents and supporters of the Livestock Festival, the Brinsons shared their duty as Grand Marshalls with Georgia's Agriculture Commissioner Gary Black in Saturday's parade.