Harry Oster, who was probably the leading collector of the music of Louisiana music issued quite a number of recordings on Chris Strachwitz's Arhoolie label. In particular there were two LPs called Folksongs of the Louisiana Acadians, now transferred to CD I imagine, which should contain some of the material you're interested in.

Also, Swallow onced released a stunning 2 LP compilation of field recordings called Louisiana Cajun and Creole Music 1934: The Lomax Recordings. Swallow. LP-8003-2. Swallow is still in existence, so again, they may have been transferred to CD.

Also, check the Smithsonian Folkways site. Folkways issued at least two LPs of Cajun folkmusic including

Cajun Songs From Louisiana. Folkways. FE 4438 which contains the unforgettable title LES MARINGOUINS ONT MANGE MA BELLE. It means The Mosquitos Have Eaten My girlfriend.

You can download anything from the Folkways catalogue at http://www.folkways.si.edu/ for just 99c a track.