Uncle Sam; Rothsville, Pennsylvania, USA; April 16, 2004.
The world's longest goat horns measured a tip-to-tip spread of 132 cm (52 in) on April 16, 2004 and belong to 'Uncle Sam' the goat, who is owned by William A and Vivian A Wentling (both USA) of Rothsville, Pennsylvania, USA.
Source: Guinness World Records 2007