Cattle in the north and west are mostly only handled and transported in the dry season, It’s just too hot otherwise.
We are further south, and our trips a maximum of around 10hrs, so we sometimes shift cattle in hot weather but try to do it at night if possible.
Those trailers are pretty much a standard design across the country and I’ve never seen one with a roof, except those carrying pigs.
The trucks would only be hooked up to negotiate the crossing, particularly the dry sandy riverbed.
In the wet season, I reckon that “river” would be raging torrent, 100+ metres wide