I was at TJ yesterday and I saw 'Sherperd's Pie'. On the box, the meat looked suspiciously like ground beef. Looked at the ingredients and I was right.
Now, having been to Ireland several times(seen shepherds) and having in-laws who are Irish and only 1 generation removed from Ireland, I'm pretty sure a Shepherd's pie has lamb. Maybe that's just me.
A cottage pie has beef.