Needed: an Argentinean cowboy song

My wife is a music teacher in an elementary school. She wants to find an Argentinean cowboy song, suitable for singing by fourth-graders. (She already promised the fourth-grade teacher she would look for one, thinking it would be easy. Well, it hasn't been easy, even after I tried helping her.)

She has one good Argentinean song, VIVA JUJUY (lyrics here, recording here), in one of her songbooks, but it has nothing to do with cowboys. Plan B is to use that one, but she still hopes to find a cowboy song.

Our problem is that neither of us is fluent in Spanish, and we know nothing about Argentinean music. There don't seem to be any English-language web sites that supply what we want. I've found some likely Spanish-language sites (see below), with lots of songs, but the songs aren't organized by topic, and they mostly don't have tunes, only lyrics.

Once I identify a suitable song, I might be able to find the tune somewhere else, especially if it's a very popular one.

Can anyone help?

Confederacion Gaucha Argentina
http://www.confederaciongaucha.com.ar/musica/index.php

Folklore del Norte Argentino
http://www.folkloredelnorte.com.ar/cancionero/
This site claims to have over 4000 songs.

La pagina del Folklore Argentino
http://inter2.unsl.edu.ar/~mmorales/folk/