Back in the early to mid-2000s, the folks at Waukaru were testing at least some of their bulls with the old GeneStar marker tests - and making that info available to people who were interested.
Now, as to whether or not those markers were even applicable to Shorthorns, I don't know... though some on this board may. Are the newer genomic tests applicable to SH... or principally to Angus... I'm presuming that a predominantly AN population was used in formulating those tests...
We did take those genomic test results into consideration in the past when we were using some Shorthorn sires here. Waukaru Coppertop 464 had 4 of 6 GeneStar tenderness markers and 2 of 4 marbling gene markers, and got moderate use here for that reason, among others.
Several of the Angus sires we were using at that same time had 5 or 6 of the 6 tenderness gene markers identified by the GeneStar test.