Last week we did a whole series on letters of recommendation. One of the most complex is for those applying for internships. Therefore, I created a (relatively simple) flowchart to help you decide what letters of recommendation you should get for internship applications.
Core disciplines are internal medicine, surgery, and emergency/critical care.
Ancillary disciplines are cardiology, neurology, oncology, anesthesiology, and radiology.
Peripheral disciplines are anyone outside your species focus (e.g. you are applying for a large animal rotating internship and the letter-writer is a small animal internist), ophthalmology, dermatology, pathology, behavior, theriogenology, and ABVP specialties.