Once you’ve identified mentors to write you a letter of recommendation (LOR), the next step is to reach out to them to ask that they write said letter. In that process, you might want to write a cover letter which provides them with some information to help them write the LOR.
Why write a cover letter? The cover letter provides some information to the individual writing your LOR. In some instances- such as if you’re having a specialty faculty member write an LOR for an internship or residency- this is unnecessary. The writer knows the deal, knows the positions, and hopefully knows you. In other instances- such as if the writer isn’t a veterinarian or you’re applying for a unique position- it can be very helpful. The writer needs direction about what, exactly, to say. When in doubt, ask your mentors if they think a cover letter COULD be useful.
What to include in a cover letter? It doesn’t need to be long. In fact, the shorter, the better; one page should be your maximum. I would start with thanking the letter writer for being willing to write you a LOR. Next, introduce the position to which you are applying and why you are applying. Give a description of the position or a link to the position description. Next, indicate what you believe would be most valuable for the letter writer to include. For example, “If you can speak to my reliability and independent work, that would be particularly valuable.” Finally, conclude with more appreciation and any deadlines which are relevant.
I think a cover letter could be valuable for any applicant for any position before, and including, vet school. For internships, residencies, and faculty positions, you shouldn’t need one. Keep it simple, to the point, informative, and appreciative and you help your letter writers provide exactly what you need for your applications.