a specialty internship should be a back up plan because you dont match for a residency, not a goal. yes, specialty internships are becoming the norm, but what it gets you is an extra year of poor pay before having a "real" job.
you need 5 publications to sit for zoo boards, and that is extremely challenging to do without a residency fyi (having talked to a couple of vets doing it that way - they have been working at it for years. its hard to get 5 publications during a residency, let alone on your own without institutional backing)
or 3+ years of internship :-/ i knew a neurologist that did 3 or 4 back several years ago when a specialty internship was uncommon, and our ophtho specialty intern is now doing a 2nd ophtho internship (for 3 years of internship) because she didnt match this year...