Because the letters “b” and “v” have the same pronunciation in Spanish, they can sometimes be a bit confusing. Calling the letters “be” and “ve” sounds exactly the same, so many times you will hear other names for these letters. “Be de Burro” and “V de vaca” are one way to distinguish these letters. Another is “B grande” and “v chica”. Recently, the RAE has declared that the “v” shall be now known as “uve”, but that will still not help the spelling of words.
If you have ever had native speakers in your class, you will likely notice these letters are a big spelling problem. You might see “¿Adónde bas?” or “El agua está en el baso”. I have several language arts textbooks from Spain and Latin American countries for elementary students and you will see a section dedicated to the correct spelling of words with these letters.
Aún los pájaros confuden la Ve con la Be.
The items below were taking from “Lengua Castellana 2˚ Ciclo inicial” por “editorial cruilla” and “Nuevo Zapín 3 Lengua Castell
2nd Grade Spanish Book
3rd grade Spanish Spelling Lesson
SpanishPlans.org 
I have heard them called “V corta” and “B larga” to destinguish between the two. I actually find it really helps to explain to my students that native Spanish speakers confuse them because it helps them to realize the pronunciation is the same if said correctly. Thanks for the post!