Well, I knew what he meant, but "horsening" is definitely not a word unless he was hoping to 'christen a horse', which I would accept as a creative neologism.
You girls have been horsening poor Mariano haven't you, but he is definately right about Cabalgata... have them right here in Parque Leloir http://lapostadeleloir.blogspot.com/2008/04/cabalgatas.html
, otherwise there are enuff cabalgatas in the Sierras of Cordoba and Andes in fantastic settings, just type cabalgata and the locality of your choice in Google. Dale Mariano no llores mas por estas yeguas crueles.