Full Idea
The fact that a cow is not a horse is a candidate for a priori synthetic truth. It doesn't seem to be analytic, because you can know what a cow is without knowing what a horse is.
Gist of Idea
Knowing that a cow is not a horse seems to be a synthetic a priori truth
Source
Jonathan Dancy (Intro to Contemporary Epistemology [1985], 14.3)
Book Reference
Dancy,Jonathan: 'Introduction to Contemporary Epistemology' [Blackwell 1985], p.215