I don’t think there’s a complete list anywhere of which schools do and don’t use terminal surgeries, but I believe there are still more that use them than not. You can find up-to-date info about specific schools’ policies by googling and looking for a result from that school’s site. Generally schools don’t use purpose-bred cats and dogs anymore (probably with some exceptions), which I think is what you’re thinking of.
As for Purdue,
this is the current information. I’m not sure if the sheep or any other large animal terminal surgeries are purpose-bred, but it seems likely the sheep are, considering they’re a pretty common experimental species and the school likely wouldn’t love the biosecurity of hunting for a bunch of sheep from who knows where to bring to teaching animal housing.