The Mini Sirloin Burgers were a food item on menus at Jack in the Box. They consisted of three miniature sirloin burgers.
The item's commercial depicts a group of midget cowboys herding miniature sized cows, about the size of a gopher (comparatively shown at one point in the commercial), which are (specifically in the Jack in the Box Universe) specially used for Jack in the Box's "Mini Sirloin Burgers".
Way out West [echo the same words] There's a story told [echo the same words (minus "there's a)] About a bunch of cowboys Tiny & Bold [echo "Tiny and Bold"] Riding Tall [echo the same words] Tall in the Saddle; herding cows the size of schnouzers, but they're cattle. [main voice and background echo voices] Yipiyaiyay Mini Sirloin Burgers, Yipiyaiyo Mini Sirloin Burgers, Yipiyaiyay Mini Sirloin Burgerrrrrs.....Yeah!
This commercial has two versions, one from early 2009 with the old logo, and one from late 2009 with the new logo.